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1
CHANGES
1
CHANGES
@@ -1,4 +1,5 @@
|
||||
|
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--- 9.4.2 released ---
|
||||
--- 9.4.2rc2 released ---
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2259. [bug] Reverse incorrect LIBINTERFACE bump of libisc
|
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|
||||
781
FAQ
781
FAQ
@@ -0,0 +1,781 @@
|
||||
Frequently Asked Questions about BIND 9
|
||||
|
||||
Copyright © 2004-2007 Internet Systems Consortium, Inc. ("ISC")
|
||||
|
||||
Copyright © 2000-2003 Internet Software Consortium.
|
||||
|
||||
-----------------------------------------------------------------------
|
||||
|
||||
1. Compilation and Installation Questions
|
||||
|
||||
Q: I'm trying to compile BIND 9, and "make" is failing due to files not
|
||||
being found. Why?
|
||||
|
||||
A: Using a parallel or distributed "make" to build BIND 9 is not
|
||||
supported, and doesn't work. If you are using one of these, use normal
|
||||
make or gmake instead.
|
||||
|
||||
Q: Isn't "make install" supposed to generate a default named.conf?
|
||||
|
||||
A: Short Answer: No.
|
||||
|
||||
Long Answer: There really isn't a default configuration which fits any
|
||||
site perfectly. There are lots of decisions that need to be made and
|
||||
there is no consensus on what the defaults should be. For example
|
||||
FreeBSD uses /etc/namedb as the location where the configuration files
|
||||
for named are stored. Others use /var/named.
|
||||
|
||||
What addresses to listen on? For a laptop on the move a lot you may
|
||||
only want to listen on the loop back interfaces.
|
||||
|
||||
Who do you offer recursive service to? Is there are firewall to
|
||||
consider? If so is it stateless or stateful. Are you directly on the
|
||||
Internet? Are you on a private network? Are you on a NAT'd network? The
|
||||
answers to all these questions change how you configure even a caching
|
||||
name server.
|
||||
|
||||
2. Configuration and Setup Questions
|
||||
|
||||
Q: Why does named log the warning message "no TTL specified - using SOA
|
||||
MINTTL instead"?
|
||||
|
||||
A: Your zone file is illegal according to RFC1035. It must either have a
|
||||
line like:
|
||||
|
||||
$TTL 86400
|
||||
|
||||
at the beginning, or the first record in it must have a TTL field, like
|
||||
the "84600" in this example:
|
||||
|
||||
example.com. 86400 IN SOA ns hostmaster ( 1 3600 1800 1814400 3600 )
|
||||
|
||||
Q: Why do I get errors like "dns_zone_load: zone foo/IN: loading master
|
||||
file bar: ran out of space"?
|
||||
|
||||
A: This is often caused by TXT records with missing close quotes. Check
|
||||
that all TXT records containing quoted strings have both open and close
|
||||
quotes.
|
||||
|
||||
Q: How do I restrict people from looking up the server version?
|
||||
|
||||
A: Put a "version" option containing something other than the real version
|
||||
in the "options" section of named.conf. Note doing this will not
|
||||
prevent attacks and may impede people trying to diagnose problems with
|
||||
your server. Also it is possible to "fingerprint" nameservers to
|
||||
determine their version.
|
||||
|
||||
Q: How do I restrict only remote users from looking up the server version?
|
||||
|
||||
A: The following view statement will intercept lookups as the internal
|
||||
view that holds the version information will be matched last. The
|
||||
caveats of the previous answer still apply, of course.
|
||||
|
||||
view "chaos" chaos {
|
||||
match-clients { <those to be refused>; };
|
||||
allow-query { none; };
|
||||
zone "." {
|
||||
type hint;
|
||||
file "/dev/null"; // or any empty file
|
||||
};
|
||||
};
|
||||
|
||||
Q: What do "no source of entropy found" or "could not open entropy source
|
||||
foo" mean?
|
||||
|
||||
A: The server requires a source of entropy to perform certain operations,
|
||||
mostly DNSSEC related. These messages indicate that you have no source
|
||||
of entropy. On systems with /dev/random or an equivalent, it is used by
|
||||
default. A source of entropy can also be defined using the
|
||||
random-device option in named.conf.
|
||||
|
||||
Q: I'm trying to use TSIG to authenticate dynamic updates or zone
|
||||
transfers. I'm sure I have the keys set up correctly, but the server is
|
||||
rejecting the TSIG. Why?
|
||||
|
||||
A: This may be a clock skew problem. Check that the the clocks on the
|
||||
client and server are properly synchronised (e.g., using ntp).
|
||||
|
||||
Q: I see a log message like the following. Why?
|
||||
|
||||
couldn't open pid file '/var/run/named.pid': Permission denied
|
||||
|
||||
A: You are most likely running named as a non-root user, and that user
|
||||
does not have permission to write in /var/run. The common ways of
|
||||
fixing this are to create a /var/run/named directory owned by the named
|
||||
user and set pid-file to "/var/run/named/named.pid", or set pid-file to
|
||||
"named.pid", which will put the file in the directory specified by the
|
||||
directory option (which, in this case, must be writable by the named
|
||||
user).
|
||||
|
||||
Q: I can query the nameserver from the nameserver but not from other
|
||||
machines. Why?
|
||||
|
||||
A: This is usually the result of the firewall configuration stopping the
|
||||
queries and / or the replies.
|
||||
|
||||
Q: How can I make a server a slave for both an internal and an external
|
||||
view at the same time? When I tried, both views on the slave were
|
||||
transferred from the same view on the master.
|
||||
|
||||
A: You will need to give the master and slave multiple IP addresses and
|
||||
use those to make sure you reach the correct view on the other machine.
|
||||
|
||||
Master: 10.0.1.1 (internal), 10.0.1.2 (external, IP alias)
|
||||
internal:
|
||||
match-clients { !10.0.1.2; !10.0.1.4; 10.0.1/24; };
|
||||
notify-source 10.0.1.1;
|
||||
transfer-source 10.0.1.1;
|
||||
query-source address 10.0.1.1;
|
||||
external:
|
||||
match-clients { any; };
|
||||
recursion no; // don't offer recursion to the world
|
||||
notify-source 10.0.1.2;
|
||||
transfer-source 10.0.1.2;
|
||||
query-source address 10.0.1.2;
|
||||
|
||||
Slave: 10.0.1.3 (internal), 10.0.1.4 (external, IP alias)
|
||||
internal:
|
||||
match-clients { !10.0.1.2; !10.0.1.4; 10.0.1/24; };
|
||||
notify-source 10.0.1.3;
|
||||
transfer-source 10.0.1.3;
|
||||
query-source address 10.0.1.3;
|
||||
external:
|
||||
match-clients { any; };
|
||||
recursion no; // don't offer recursion to the world
|
||||
notify-source 10.0.1.4;
|
||||
transfer-source 10.0.1.4;
|
||||
query-source address 10.0.1.4;
|
||||
|
||||
You put the external address on the alias so that all the other dns
|
||||
clients on these boxes see the internal view by default.
|
||||
|
||||
A: BIND 9.3 and later: Use TSIG to select the appropriate view.
|
||||
|
||||
Master 10.0.1.1:
|
||||
key "external" {
|
||||
algorithm hmac-md5;
|
||||
secret "xxxxxxxx";
|
||||
};
|
||||
view "internal" {
|
||||
match-clients { !key external; 10.0.1/24; };
|
||||
...
|
||||
};
|
||||
view "external" {
|
||||
match-clients { key external; any; };
|
||||
server 10.0.1.2 { keys external; };
|
||||
recursion no;
|
||||
...
|
||||
};
|
||||
|
||||
Slave 10.0.1.2:
|
||||
key "external" {
|
||||
algorithm hmac-md5;
|
||||
secret "xxxxxxxx";
|
||||
};
|
||||
view "internal" {
|
||||
match-clients { !key external; 10.0.1/24; };
|
||||
...
|
||||
};
|
||||
view "external" {
|
||||
match-clients { key external; any; };
|
||||
server 10.0.1.1 { keys external; };
|
||||
recursion no;
|
||||
...
|
||||
};
|
||||
|
||||
Q: I get error messages like "multiple RRs of singleton type" and "CNAME
|
||||
and other data" when transferring a zone. What does this mean?
|
||||
|
||||
A: These indicate a malformed master zone. You can identify the exact
|
||||
records involved by transferring the zone using dig then running
|
||||
named-checkzone on it.
|
||||
|
||||
dig axfr example.com @master-server > tmp
|
||||
named-checkzone example.com tmp
|
||||
|
||||
A CNAME record cannot exist with the same name as another record except
|
||||
for the DNSSEC records which prove its existence (NSEC).
|
||||
|
||||
RFC 1034, Section 3.6.2: "If a CNAME RR is present at a node, no other
|
||||
data should be present; this ensures that the data for a canonical name
|
||||
and its aliases cannot be different. This rule also insures that a
|
||||
cached CNAME can be used without checking with an authoritative server
|
||||
for other RR types."
|
||||
|
||||
Q: I get error messages like "named.conf:99: unexpected end of input"
|
||||
where 99 is the last line of named.conf.
|
||||
|
||||
A: Some text editors (notepad and wordpad) fail to put a line title
|
||||
indication (e.g. CR/LF) on the last line of a text file. This can be
|
||||
fixed by "adding" a blank line to the end of the file. Named expects to
|
||||
see EOF immediately after EOL and treats text files where this is not
|
||||
met as truncated.
|
||||
|
||||
Q: How do I share a dynamic zone between multiple views?
|
||||
|
||||
A: You choose one view to be master and the second a slave and transfer
|
||||
the zone between views.
|
||||
|
||||
Master 10.0.1.1:
|
||||
key "external" {
|
||||
algorithm hmac-md5;
|
||||
secret "xxxxxxxx";
|
||||
};
|
||||
|
||||
key "mykey" {
|
||||
algorithm hmac-md5;
|
||||
secret "yyyyyyyy";
|
||||
};
|
||||
|
||||
view "internal" {
|
||||
match-clients { !key external; 10.0.1/24; };
|
||||
server 10.0.1.1 {
|
||||
/* Deliver notify messages to external view. */
|
||||
keys { external; };
|
||||
};
|
||||
zone "example.com" {
|
||||
type master;
|
||||
file "internal/example.db";
|
||||
allow-update { key mykey; };
|
||||
notify-also { 10.0.1.1; };
|
||||
};
|
||||
};
|
||||
|
||||
view "external" {
|
||||
match-clients { key external; any; };
|
||||
zone "example.com" {
|
||||
type slave;
|
||||
file "external/example.db";
|
||||
masters { 10.0.1.1; };
|
||||
transfer-source { 10.0.1.1; };
|
||||
// allow-update-forwarding { any; };
|
||||
// allow-notify { ... };
|
||||
};
|
||||
};
|
||||
|
||||
Q: I get a error message like "zone wireless.ietf56.ietf.org/IN: loading
|
||||
master file primaries/wireless.ietf56.ietf.org: no owner".
|
||||
|
||||
A: This error is produced when a line in the master file contains leading
|
||||
white space (tab/space) but the is no current record owner name to
|
||||
inherit the name from. Usually this is the result of putting white
|
||||
space before a comment, forgetting the "@" for the SOA record, or
|
||||
indenting the master file.
|
||||
|
||||
Q: Why are my logs in GMT (UTC).
|
||||
|
||||
A: You are running chrooted (-t) and have not supplied local timezone
|
||||
information in the chroot area.
|
||||
|
||||
FreeBSD: /etc/localtime
|
||||
Solaris: /etc/TIMEZONE and /usr/share/lib/zoneinfo
|
||||
OSF: /etc/zoneinfo/localtime
|
||||
|
||||
See also tzset(3) and zic(8).
|
||||
|
||||
Q: I get "rndc: connect failed: connection refused" when I try to run
|
||||
rndc.
|
||||
|
||||
A: This is usually a configuration error.
|
||||
|
||||
First ensure that named is running and no errors are being reported at
|
||||
startup (/var/log/messages or equivalent). Running "named -g <usual
|
||||
arguments>" from a title can help at this point.
|
||||
|
||||
Secondly ensure that named is configured to use rndc either by
|
||||
"rndc-confgen -a", rndc-confgen or manually. The Administrators
|
||||
Reference manual has details on how to do this.
|
||||
|
||||
Old versions of rndc-confgen used localhost rather than 127.0.0.1 in /
|
||||
etc/rndc.conf for the default server. Update /etc/rndc.conf if
|
||||
necessary so that the default server listed in /etc/rndc.conf matches
|
||||
the addresses used in named.conf. "localhost" has two address
|
||||
(127.0.0.1 and ::1).
|
||||
|
||||
If you use "rndc-confgen -a" and named is running with -t or -u ensure
|
||||
that /etc/rndc.conf has the correct ownership and that a copy is in the
|
||||
chroot area. You can do this by re-running "rndc-confgen -a" with
|
||||
appropriate -t and -u arguments.
|
||||
|
||||
Q: I get "transfer of 'example.net/IN' from 192.168.4.12#53: failed while
|
||||
receiving responses: permission denied" error messages.
|
||||
|
||||
A: These indicate a filesystem permission error preventing named creating
|
||||
/ renaming the temporary file. These will usually also have other
|
||||
associated error messages like
|
||||
|
||||
"dumping master file: sl/tmp-XXXX5il3sQ: open: permission denied"
|
||||
|
||||
Named needs write permission on the directory containing the file.
|
||||
Named writes the new cache file to a temporary file then renames it to
|
||||
the name specified in named.conf to ensure that the contents are always
|
||||
complete. This is to prevent named loading a partial zone in the event
|
||||
of power failure or similar interrupting the write of the master file.
|
||||
|
||||
Note file names are relative to the directory specified in options and
|
||||
any chroot directory ([<chroot dir>/][<options dir>]).
|
||||
|
||||
If named is invoked as "named -t /chroot/DNS" with the following
|
||||
named.conf then "/chroot/DNS/var/named/sl" needs to be writable by the
|
||||
user named is running as.
|
||||
|
||||
options {
|
||||
directory "/var/named";
|
||||
};
|
||||
|
||||
zone "example.net" {
|
||||
type slave;
|
||||
file "sl/example.net";
|
||||
masters { 192.168.4.12; };
|
||||
};
|
||||
|
||||
Q: I want to forward all DNS queries from my caching nameserver to another
|
||||
server. But there are some domains which have to be served locally, via
|
||||
rbldnsd.
|
||||
|
||||
How do I achieve this ?
|
||||
|
||||
A: options {
|
||||
forward only;
|
||||
forwarders { <ip.of.primary.nameserver>; };
|
||||
};
|
||||
|
||||
zone "sbl-xbl.spamhaus.org" {
|
||||
type forward; forward only;
|
||||
forwarders { <ip.of.rbldns.server> port 530; };
|
||||
};
|
||||
|
||||
zone "list.dsbl.org" {
|
||||
type forward; forward only;
|
||||
forwarders { <ip.of.rbldns.server> port 530; };
|
||||
};
|
||||
|
||||
|
||||
Q: Can you help me understand how BIND 9 uses memory to store DNS zones?
|
||||
|
||||
Some times it seems to take several times the amount of memory it needs
|
||||
to store the zone.
|
||||
|
||||
A: When reloading a zone named my have multiple copies of the zone in
|
||||
memory at one time. The zone it is serving and the one it is loading.
|
||||
If reloads are ultra fast it can have more still.
|
||||
|
||||
e.g. Ones that are transferring out, the one that it is serving and the
|
||||
one that is loading.
|
||||
|
||||
BIND 8 destroyed the zone before loading and also killed off outgoing
|
||||
transfers of the zone.
|
||||
|
||||
The new strategy allows slaves to get copies of the new zone regardless
|
||||
of how often the master is loaded compared to the transfer time. The
|
||||
slave might skip some intermediate versions but the transfers will
|
||||
complete and it will keep reasonably in sync with the master.
|
||||
|
||||
The new strategy also allows the master to recover from syntax and
|
||||
other errors in the master file as it still has an in-core copy of the
|
||||
old contents.
|
||||
|
||||
3. General Questions
|
||||
|
||||
Q: I keep getting log messages like the following. Why?
|
||||
|
||||
Dec 4 23:47:59 client 10.0.0.1#1355: updating zone 'example.com/IN':
|
||||
update failed: 'RRset exists (value dependent)' prerequisite not
|
||||
satisfied (NXRRSET)
|
||||
|
||||
A: DNS updates allow the update request to test to see if certain
|
||||
conditions are met prior to proceeding with the update. The message
|
||||
above is saying that conditions were not met and the update is not
|
||||
proceeding. See doc/rfc/rfc2136.txt for more details on prerequisites.
|
||||
|
||||
Q: I keep getting log messages like the following. Why?
|
||||
|
||||
Jun 21 12:00:00.000 client 10.0.0.1#1234: update denied
|
||||
|
||||
A: Someone is trying to update your DNS data using the RFC2136 Dynamic
|
||||
Update protocol. Windows 2000 machines have a habit of sending dynamic
|
||||
update requests to DNS servers without being specifically configured to
|
||||
do so. If the update requests are coming from a Windows 2000 machine,
|
||||
see http://support.microsoft.com/support/kb/articles/q246/8/04.asp for
|
||||
information about how to turn them off.
|
||||
|
||||
Q: When I do a "dig . ns", many of the A records for the root servers are
|
||||
missing. Why?
|
||||
|
||||
A: This is normal and harmless. It is a somewhat confusing side effect of
|
||||
the way BIND 9 does RFC2181 trust ranking and of the efforts BIND 9
|
||||
makes to avoid promoting glue into answers.
|
||||
|
||||
When BIND 9 first starts up and primes its cache, it receives the root
|
||||
server addresses as additional data in an authoritative response from a
|
||||
root server, and these records are eligible for inclusion as additional
|
||||
data in responses. Subsequently it receives a subset of the root server
|
||||
addresses as additional data in a non-authoritative (referral) response
|
||||
from a root server. This causes the addresses to now be considered
|
||||
non-authoritative (glue) data, which is not eligible for inclusion in
|
||||
responses.
|
||||
|
||||
The server does have a complete set of root server addresses cached at
|
||||
all times, it just may not include all of them as additional data,
|
||||
depending on whether they were last received as answers or as glue. You
|
||||
can always look up the addresses with explicit queries like "dig
|
||||
a.root-servers.net A".
|
||||
|
||||
Q: Why don't my zones reload when I do an "rndc reload" or SIGHUP?
|
||||
|
||||
A: A zone can be updated either by editing zone files and reloading the
|
||||
server or by dynamic update, but not both. If you have enabled dynamic
|
||||
update for a zone using the "allow-update" option, you are not supposed
|
||||
to edit the zone file by hand, and the server will not attempt to
|
||||
reload it.
|
||||
|
||||
Q: Why is named listening on UDP port other than 53?
|
||||
|
||||
A: Named uses a system selected port to make queries of other nameservers.
|
||||
This behaviour can be overridden by using query-source to lock down the
|
||||
port and/or address. See also notify-source and transfer-source.
|
||||
|
||||
Q: I get warning messages like "zone example.com/IN: refresh: failure
|
||||
trying master 1.2.3.4#53: timed out".
|
||||
|
||||
A: Check that you can make UDP queries from the slave to the master
|
||||
|
||||
dig +norec example.com soa @1.2.3.4
|
||||
|
||||
You could be generating queries faster than the slave can cope with.
|
||||
Lower the serial query rate.
|
||||
|
||||
serial-query-rate 5; // default 20
|
||||
|
||||
Q: I don't get RRSIG's returned when I use "dig +dnssec".
|
||||
|
||||
A: You need to ensure DNSSEC is enabled (dnssec-enable yes;).
|
||||
|
||||
Q: Can a NS record refer to a CNAME.
|
||||
|
||||
A: No. The rules for glue (copies of the *address* records in the parent
|
||||
zones) and additional section processing do not allow it to work.
|
||||
|
||||
You would have to add both the CNAME and address records (A/AAAA) as
|
||||
glue to the parent zone and have CNAMEs be followed when doing
|
||||
additional section processing to make it work. No nameserver
|
||||
implementation supports either of these requirements.
|
||||
|
||||
Q: What does "RFC 1918 response from Internet for 0.0.0.10.IN-ADDR.ARPA"
|
||||
mean?
|
||||
|
||||
A: If the IN-ADDR.ARPA name covered refers to a internal address space you
|
||||
are using then you have failed to follow RFC 1918 usage rules and are
|
||||
leaking queries to the Internet. You should establish your own zones
|
||||
for these addresses to prevent you querying the Internet's name servers
|
||||
for these addresses. Please see http://as112.net/ for details of the
|
||||
problems you are causing and the counter measures that have had to be
|
||||
deployed.
|
||||
|
||||
If you are not using these private addresses then a client has queried
|
||||
for them. You can just ignore the messages, get the offending client to
|
||||
stop sending you these messages as they are most probably leaking them
|
||||
or setup your own zones empty zones to serve answers to these queries.
|
||||
|
||||
zone "10.IN-ADDR.ARPA" {
|
||||
type master;
|
||||
file "empty";
|
||||
};
|
||||
|
||||
zone "16.172.IN-ADDR.ARPA" {
|
||||
type master;
|
||||
file "empty";
|
||||
};
|
||||
|
||||
...
|
||||
|
||||
zone "31.172.IN-ADDR.ARPA" {
|
||||
type master;
|
||||
file "empty";
|
||||
};
|
||||
|
||||
zone "168.192.IN-ADDR.ARPA" {
|
||||
type master;
|
||||
file "empty";
|
||||
};
|
||||
|
||||
empty:
|
||||
@ 10800 IN SOA <name-of-server>. <contact-email>. (
|
||||
1 3600 1200 604800 10800 )
|
||||
@ 10800 IN NS <name-of-server>.
|
||||
|
||||
Note
|
||||
|
||||
Future versions of named are likely to do this automatically.
|
||||
|
||||
Q: Will named be affected by the 2007 changes to daylight savings rules in
|
||||
the US.
|
||||
|
||||
A: No, so long as the machines internal clock (as reported by "date -u")
|
||||
remains at UTC. The only visible change if you fail to upgrade your OS,
|
||||
if you are in a affected area, will be that log messages will be a hour
|
||||
out during the period where the old rules do not match the new rules.
|
||||
|
||||
For most OS's this change just means that you need to update the
|
||||
conversion rules from UTC to local time. Normally this involves
|
||||
updating a file in /etc (which sets the default timezone for the
|
||||
machine) and possibly a directory which has all the conversion rules
|
||||
for the world (e.g. /usr/share/zoneinfo). When updating the OS do not
|
||||
forget to update any chroot areas as well. See your OS's documentation
|
||||
for more details.
|
||||
|
||||
The local timezone conversion rules can also be done on a individual
|
||||
basis by setting the TZ environment variable appropriately. See your
|
||||
OS's documentation for more details.
|
||||
|
||||
Q: Is there a bugzilla (or other tool) database that mere mortals can have
|
||||
(read-only) access to for bind?
|
||||
|
||||
A: No. The BIND 9 bug database is kept closed for a number of reasons.
|
||||
These include, but are not limited to, that the database contains
|
||||
proprietory information from people reporting bugs. The database has in
|
||||
the past and may in future contain unfixed bugs which are capable of
|
||||
bringing down most of the Internet's DNS infrastructure.
|
||||
|
||||
The release pages for each version contain up to date lists of bugs
|
||||
that have been fixed post release. That is as close as we can get to
|
||||
providing a bug database.
|
||||
|
||||
4. Operating-System Specific Questions
|
||||
|
||||
4.1. HPUX
|
||||
|
||||
Q: I get the following error trying to configure BIND:
|
||||
|
||||
checking if unistd.h or sys/types.h defines fd_set... no
|
||||
configure: error: need either working unistd.h or sys/select.h
|
||||
|
||||
A: You have attempted to configure BIND with the bundled C compiler. This
|
||||
compiler does not meet the minimum compiler requirements to for
|
||||
building BIND. You need to install a ANSI C compiler and / or teach
|
||||
configure how to find the ANSI C compiler. The later can be done by
|
||||
adjusting the PATH environment variable and / or specifying the
|
||||
compiler via CC.
|
||||
|
||||
./configure CC=<compiler> ...
|
||||
|
||||
4.2. Linux
|
||||
|
||||
Q: Why do I get the following errors:
|
||||
|
||||
general: errno2result.c:109: unexpected error:
|
||||
general: unable to convert errno to isc_result: 14: Bad address
|
||||
client: UDP client handler shutting down due to fatal receive error: unexpected error
|
||||
|
||||
A: This is the result of a Linux kernel bug.
|
||||
|
||||
See: http://marc.theaimsgroup.com/?l=linux-netdev&m=113081708031466&w=2
|
||||
|
||||
Q: Why do I see 5 (or more) copies of named on Linux?
|
||||
|
||||
A: Linux threads each show up as a process under ps. The approximate
|
||||
number of threads running is n+4, where n is the number of CPUs. Note
|
||||
that the amount of memory used is not cumulative; if each process is
|
||||
using 10M of memory, only a total of 10M is used.
|
||||
|
||||
Newer versions of Linux's ps command hide the individual threads and
|
||||
require -L to display them.
|
||||
|
||||
Q: Why does BIND 9 log "permission denied" errors accessing its
|
||||
configuration files or zones on my Linux system even though it is
|
||||
running as root?
|
||||
|
||||
A: On Linux, BIND 9 drops most of its root privileges on startup. This
|
||||
including the privilege to open files owned by other users. Therefore,
|
||||
if the server is running as root, the configuration files and zone
|
||||
files should also be owned by root.
|
||||
|
||||
Q: I get the error message "named: capset failed: Operation not permitted"
|
||||
when starting named.
|
||||
|
||||
A: The capability module, part of "Linux Security Modules/LSM", has not
|
||||
been loaded into the kernel. See insmod(8).
|
||||
|
||||
Q: I'm running BIND on Red Hat Enterprise Linux or Fedora Core -
|
||||
|
||||
Why can't named update slave zone database files?
|
||||
|
||||
Why can't named create DDNS journal files or update the master zones
|
||||
from journals?
|
||||
|
||||
Why can't named create custom log files?
|
||||
|
||||
A: Red Hat Security Enhanced Linux (SELinux) policy security protections :
|
||||
|
||||
Red Hat have adopted the National Security Agency's SELinux security
|
||||
policy ( see http://www.nsa.gov/selinux ) and recommendations for BIND
|
||||
security , which are more secure than running named in a chroot and
|
||||
make use of the bind-chroot environment unnecessary .
|
||||
|
||||
By default, named is not allowed by the SELinux policy to write, create
|
||||
or delete any files EXCEPT in these directories:
|
||||
|
||||
$ROOTDIR/var/named/slaves
|
||||
$ROOTDIR/var/named/data
|
||||
$ROOTDIR/var/tmp
|
||||
|
||||
|
||||
where $ROOTDIR may be set in /etc/sysconfig/named if bind-chroot is
|
||||
installed.
|
||||
|
||||
The SELinux policy particularly does NOT allow named to modify the
|
||||
$ROOTDIR/var/named directory, the default location for master zone
|
||||
database files.
|
||||
|
||||
SELinux policy overrules file access permissions - so even if all the
|
||||
files under /var/named have ownership named:named and mode rw-rw-r--,
|
||||
named will still not be able to write or create files except in the
|
||||
directories above, with SELinux in Enforcing mode.
|
||||
|
||||
So, to allow named to update slave or DDNS zone files, it is best to
|
||||
locate them in $ROOTDIR/var/named/slaves, with named.conf zone
|
||||
statements such as:
|
||||
|
||||
zone "slave.zone." IN {
|
||||
type slave;
|
||||
file "slaves/slave.zone.db";
|
||||
...
|
||||
};
|
||||
zone "ddns.zone." IN {
|
||||
type master;
|
||||
allow-updates {...};
|
||||
file "slaves/ddns.zone.db";
|
||||
};
|
||||
|
||||
|
||||
To allow named to create its cache dump and statistics files, for
|
||||
example, you could use named.conf options statements such as:
|
||||
|
||||
options {
|
||||
...
|
||||
dump-file "/var/named/data/cache_dump.db";
|
||||
statistics-file "/var/named/data/named_stats.txt";
|
||||
...
|
||||
};
|
||||
|
||||
|
||||
You can also tell SELinux to allow named to update any zone database
|
||||
files, by setting the SELinux tunable boolean parameter
|
||||
'named_write_master_zones=1', using the system-config-securitylevel
|
||||
GUI, using the 'setsebool' command, or in /etc/selinux/targeted/
|
||||
booleans.
|
||||
|
||||
You can disable SELinux protection for named entirely by setting the
|
||||
'named_disable_trans=1' SELinux tunable boolean parameter.
|
||||
|
||||
The SELinux named policy defines these SELinux contexts for named:
|
||||
|
||||
named_zone_t : for zone database files - $ROOTDIR/var/named/*
|
||||
named_conf_t : for named configuration files - $ROOTDIR/etc/{named,rndc}.*
|
||||
named_cache_t: for files modifiable by named - $ROOTDIR/var/{tmp,named/{slaves,data}}
|
||||
|
||||
|
||||
If you want to retain use of the SELinux policy for named, and put
|
||||
named files in different locations, you can do so by changing the
|
||||
context of the custom file locations .
|
||||
|
||||
To create a custom configuration file location, e.g. '/root/
|
||||
named.conf', to use with the 'named -c' option, do:
|
||||
|
||||
# chcon system_u:object_r:named_conf_t /root/named.conf
|
||||
|
||||
|
||||
To create a custom modifiable named data location, e.g. '/var/log/
|
||||
named' for a log file, do:
|
||||
|
||||
# chcon system_u:object_r:named_cache_t /var/log/named
|
||||
|
||||
|
||||
To create a custom zone file location, e.g. /root/zones/, do:
|
||||
|
||||
# chcon system_u:object_r:named_zone_t /root/zones/{.,*}
|
||||
|
||||
|
||||
See these man-pages for more information : selinux(8), named_selinux
|
||||
(8), chcon(1), setsebool(8)
|
||||
|
||||
4.3. Windows
|
||||
|
||||
Q: Zone transfers from my BIND 9 master to my Windows 2000 slave fail.
|
||||
Why?
|
||||
|
||||
A: This may be caused by a bug in the Windows 2000 DNS server where DNS
|
||||
messages larger than 16K are not handled properly. This can be worked
|
||||
around by setting the option "transfer-format one-answer;". Also check
|
||||
whether your zone contains domain names with embedded spaces or other
|
||||
special characters, like "John\032Doe\213s\032Computer", since such
|
||||
names have been known to cause Windows 2000 slaves to incorrectly
|
||||
reject the zone.
|
||||
|
||||
Q: I get "Error 1067" when starting named under Windows.
|
||||
|
||||
A: This is the service manager saying that named exited. You need to
|
||||
examine the Application log in the EventViewer to find out why.
|
||||
|
||||
Common causes are that you failed to create "named.conf" (usually "C:\
|
||||
windows\dns\etc\named.conf") or failed to specify the directory in
|
||||
named.conf.
|
||||
|
||||
options {
|
||||
Directory "C:\windows\dns\etc";
|
||||
};
|
||||
|
||||
4.4. FreeBSD
|
||||
|
||||
Q: I have FreeBSD 4.x and "rndc-confgen -a" just sits there.
|
||||
|
||||
A: /dev/random is not configured. Use rndcontrol(8) to tell the kernel to
|
||||
use certain interrupts as a source of random events. You can make this
|
||||
permanent by setting rand_irqs in /etc/rc.conf.
|
||||
|
||||
/etc/rc.conf
|
||||
rand_irqs="3 14 15"
|
||||
|
||||
See also http://people.freebsd.org/~dougb/randomness.html
|
||||
|
||||
4.5. Solaris
|
||||
|
||||
Q: How do I integrate BIND 9 and Solaris SMF
|
||||
|
||||
A: Sun has a blog entry describing how to do this.
|
||||
|
||||
http://blogs.sun.com/roller/page/anay/Weblog?catname=%2FSolaris
|
||||
|
||||
4.6. Apple Mac OS X
|
||||
|
||||
Q: How do I run BIND 9 on Apple Mac OS X?
|
||||
|
||||
A: If you run Tiger(Mac OS 10.4) or later then this is all you need to do:
|
||||
|
||||
% sudo rndc-confgen > /etc/rndc.conf
|
||||
|
||||
Copy the key statement from /etc/rndc.conf into /etc/rndc.key, e.g.:
|
||||
|
||||
key "rndc-key" {
|
||||
algorithm hmac-md5;
|
||||
secret "uvceheVuqf17ZwIcTydddw==";
|
||||
};
|
||||
|
||||
Then start the relevant service:
|
||||
|
||||
% sudo service org.isc.named start
|
||||
|
||||
This is persistent upon a reboot, so you will have to do it only once.
|
||||
|
||||
A: Alternatively you can just generate /etc/rndc.key by running:
|
||||
|
||||
% sudo rndc-confgen -a
|
||||
|
||||
Then start the relevant service:
|
||||
|
||||
% sudo service org.isc.named start
|
||||
|
||||
Named will look for /etc/rndc.key when it starts if it doesn't have a
|
||||
controls section or the existing controls are missing keys sub-clauses.
|
||||
This is persistent upon a reboot, so you will have to do it only once.
|
||||
|
||||
|
||||
@@ -1,840 +0,0 @@
|
||||
|
||||
|
||||
|
||||
DNSEXT D. Blacka
|
||||
Internet-Draft VeriSign, Inc.
|
||||
Intended status: Standards Track April 7, 2006
|
||||
Expires: October 9, 2006
|
||||
|
||||
|
||||
DNSSEC Experiments
|
||||
draft-ietf-dnsext-dnssec-experiments-03
|
||||
|
||||
Status of this Memo
|
||||
|
||||
By submitting this Internet-Draft, each author represents that any
|
||||
applicable patent or other IPR claims of which he or she is aware
|
||||
have been or will be disclosed, and any of which he or she becomes
|
||||
aware will be disclosed, in accordance with Section 6 of BCP 79.
|
||||
|
||||
Internet-Drafts are working documents of the Internet Engineering
|
||||
Task Force (IETF), its areas, and its working groups. Note that
|
||||
other groups may also distribute working documents as Internet-
|
||||
Drafts.
|
||||
|
||||
Internet-Drafts are draft documents valid for a maximum of six months
|
||||
and may be updated, replaced, or obsoleted by other documents at any
|
||||
time. It is inappropriate to use Internet-Drafts as reference
|
||||
material or to cite them other than as "work in progress."
|
||||
|
||||
The list of current Internet-Drafts can be accessed at
|
||||
http://www.ietf.org/ietf/1id-abstracts.txt.
|
||||
|
||||
The list of Internet-Draft Shadow Directories can be accessed at
|
||||
http://www.ietf.org/shadow.html.
|
||||
|
||||
This Internet-Draft will expire on October 9, 2006.
|
||||
|
||||
Copyright Notice
|
||||
|
||||
Copyright (C) The Internet Society (2006).
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 1]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
Abstract
|
||||
|
||||
This document describes a methodology for deploying alternate, non-
|
||||
backwards-compatible, DNSSEC methodologies in an experimental fashion
|
||||
without disrupting the deployment of standard DNSSEC.
|
||||
|
||||
|
||||
Table of Contents
|
||||
|
||||
1. Definitions and Terminology . . . . . . . . . . . . . . . . . 3
|
||||
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
|
||||
3. Experiments . . . . . . . . . . . . . . . . . . . . . . . . . 5
|
||||
4. Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
|
||||
5. Defining an Experiment . . . . . . . . . . . . . . . . . . . . 8
|
||||
6. Considerations . . . . . . . . . . . . . . . . . . . . . . . . 9
|
||||
7. Use in Non-Experiments . . . . . . . . . . . . . . . . . . . . 10
|
||||
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
|
||||
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
|
||||
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
|
||||
10.1. Normative References . . . . . . . . . . . . . . . . . . 13
|
||||
10.2. Informative References . . . . . . . . . . . . . . . . . 13
|
||||
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14
|
||||
Intellectual Property and Copyright Statements . . . . . . . . . . 15
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 2]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
1. Definitions and Terminology
|
||||
|
||||
Throughout this document, familiarity with the DNS system (RFC 1035
|
||||
[5]) and the DNS security extensions ([2], [3], and [4] is assumed.
|
||||
|
||||
The key words "MUST, "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
|
||||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY, and "OPTIONAL" in this
|
||||
document are to be interpreted as described in RFC 2119 [1].
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 3]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
2. Overview
|
||||
|
||||
Historically, experimentation with DNSSEC alternatives has been a
|
||||
problematic endeavor. There has typically been a desire to both
|
||||
introduce non-backwards-compatible changes to DNSSEC and to try these
|
||||
changes on real zones in the public DNS. This creates a problem when
|
||||
the change to DNSSEC would make all or part of the zone using those
|
||||
changes appear bogus (bad) or otherwise broken to existing security-
|
||||
aware resolvers.
|
||||
|
||||
This document describes a standard methodology for setting up DNSSEC
|
||||
experiments. This methodology addresses the issue of co-existence
|
||||
with standard DNSSEC and DNS by using unknown algorithm identifiers
|
||||
to hide the experimental DNSSEC protocol modifications from standard
|
||||
security-aware resolvers.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 4]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
3. Experiments
|
||||
|
||||
When discussing DNSSEC experiments, it is necessary to classify these
|
||||
experiments into two broad categories:
|
||||
|
||||
Backwards-Compatible: describes experimental changes that, while not
|
||||
strictly adhering to the DNSSEC standard, are nonetheless
|
||||
interoperable with clients and servers that do implement the
|
||||
DNSSEC standard.
|
||||
|
||||
Non-Backwards-Compatible: describes experiments that would cause a
|
||||
standard security-aware resolver to (incorrectly) determine that
|
||||
all or part of a zone is bogus, or to otherwise not interoperate
|
||||
with standard DNSSEC clients and servers.
|
||||
|
||||
Not included in these terms are experiments with the core DNS
|
||||
protocol itself.
|
||||
|
||||
The methodology described in this document is not necessary for
|
||||
backwards-compatible experiments, although it certainly may be used
|
||||
if desired.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 5]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
4. Method
|
||||
|
||||
The core of the methodology is the use of strictly unknown algorithm
|
||||
identifiers when signing the experimental zone, and more importantly,
|
||||
having only unknown algorithm identifiers in the DS records for the
|
||||
delegation to the zone at the parent.
|
||||
|
||||
This technique works because of the way DNSSEC-compliant validators
|
||||
are expected to work in the presence of a DS set with only unknown
|
||||
algorithm identifiers. From [4], Section 5.2:
|
||||
|
||||
If the validator does not support any of the algorithms listed in
|
||||
an authenticated DS RRset, then the resolver has no supported
|
||||
authentication path leading from the parent to the child. The
|
||||
resolver should treat this case as it would the case of an
|
||||
authenticated NSEC RRset proving that no DS RRset exists, as
|
||||
described above.
|
||||
|
||||
And further:
|
||||
|
||||
If the resolver does not support any of the algorithms listed in
|
||||
an authenticated DS RRset, then the resolver will not be able to
|
||||
verify the authentication path to the child zone. In this case,
|
||||
the resolver SHOULD treat the child zone as if it were unsigned.
|
||||
|
||||
While this behavior isn't strictly mandatory (as marked by MUST), it
|
||||
is likely that a validator would implement this behavior, or, more to
|
||||
the point, it would handle this situation in a safe way (see below
|
||||
(Section 6).)
|
||||
|
||||
Because we are talking about experiments, it is RECOMMENDED that
|
||||
private algorithm numbers be used (see [3], appendix A.1.1. Note
|
||||
that secure handling of private algorithms requires special handing
|
||||
by the validator logic. See [6] for further details.) Normally,
|
||||
instead of actually inventing new signing algorithms, the recommended
|
||||
path is to create alternate algorithm identifiers that are aliases
|
||||
for the existing, known algorithms. While, strictly speaking, it is
|
||||
only necessary to create an alternate identifier for the mandatory
|
||||
algorithms, it is suggested that all optional defined algorithms be
|
||||
aliased as well.
|
||||
|
||||
It is RECOMMENDED that for a particular DNSSEC experiment, a
|
||||
particular domain name base is chosen for all new algorithms, then
|
||||
the algorithm number (or name) is prepended to it. For example, for
|
||||
experiment A, the base name of "dnssec-experiment-a.example.com" is
|
||||
chosen. Then, aliases for algorithms 3 (DSA) and 5 (RSASHA1) are
|
||||
defined to be "3.dnssec-experiment-a.example.com" and
|
||||
"5.dnssec-experiment-a.example.com". However, any unique identifier
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 6]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
will suffice.
|
||||
|
||||
Using this method, resolvers (or, more specifically, DNSSEC
|
||||
validators) essentially indicate their ability to understand the
|
||||
DNSSEC experiment's semantics by understanding what the new algorithm
|
||||
identifiers signify.
|
||||
|
||||
This method creates two classes of security-aware servers and
|
||||
resolvers: servers and resolvers that are aware of the experiment
|
||||
(and thus recognize the experiment's algorithm identifiers and
|
||||
experimental semantics), and servers and resolvers that are unaware
|
||||
of the experiment.
|
||||
|
||||
This method also precludes any zone from being both in an experiment
|
||||
and in a classic DNSSEC island of security. That is, a zone is
|
||||
either in an experiment and only experimentally validatable, or it is
|
||||
not.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 7]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
5. Defining an Experiment
|
||||
|
||||
The DNSSEC experiment MUST define the particular set of (previously
|
||||
unknown) algorithm identifiers that identify the experiment, and
|
||||
define what each unknown algorithm identifier means. Typically,
|
||||
unless the experiment is actually experimenting with a new DNSSEC
|
||||
algorithm, this will be a mapping of private algorithm identifiers to
|
||||
existing, known algorithms.
|
||||
|
||||
Normally the experiment will choose a DNS name as the algorithm
|
||||
identifier base. This DNS name SHOULD be under the control of the
|
||||
authors of the experiment. Then the experiment will define a mapping
|
||||
between known mandatory and optional algorithms into this private
|
||||
algorithm identifier space. Alternately, the experiment MAY use the
|
||||
OID private algorithm space instead (using algorithm number 254), or
|
||||
MAY choose non-private algorithm numbers, although this would require
|
||||
an IANA allocation.
|
||||
|
||||
For example, an experiment might specify in its description the DNS
|
||||
name "dnssec-experiment-a.example.com" as the base name, and declare
|
||||
that "3.dnssec-experiment-a.example.com" is an alias of DNSSEC
|
||||
algorithm 3 (DSA), and that "5.dnssec-experiment-a.example.com" is an
|
||||
alias of DNSSEC algorithm 5 (RSASHA1).
|
||||
|
||||
Resolvers MUST only recognize the experiment's semantics when present
|
||||
in a zone signed by one or more of these algorithm identifiers. This
|
||||
is necessary to isolate the semantics of one experiment from any
|
||||
others that the resolver might understand.
|
||||
|
||||
In general, resolvers involved in the experiment are expected to
|
||||
understand both standard DNSSEC and the defined experimental DNSSEC
|
||||
protocol, although this isn't required.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 8]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
6. Considerations
|
||||
|
||||
There are a number of considerations with using this methodology.
|
||||
|
||||
1. Under some circumstances, it may be that the experiment will not
|
||||
be sufficiently masked by this technique and may cause resolution
|
||||
problem for resolvers not aware of the experiment. For instance,
|
||||
the resolver may look at a non-validatable response and conclude
|
||||
that the response is bogus, either due to local policy or
|
||||
implementation details. This is not expected to be a common
|
||||
case, however.
|
||||
|
||||
2. It will not be possible for security-aware resolvers unaware of
|
||||
the experiment to build a chain of trust through an experimental
|
||||
zone.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 9]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
7. Use in Non-Experiments
|
||||
|
||||
This general methodology MAY be used for non-backwards compatible
|
||||
DNSSEC protocol changes that start out as or become standards. In
|
||||
this case:
|
||||
|
||||
o The protocol change SHOULD use public IANA allocated algorithm
|
||||
identifiers instead of private algorithm identifiers. This will
|
||||
help identify the protocol change as a standard, rather than an
|
||||
experiment.
|
||||
|
||||
o Resolvers MAY recognize the protocol change in zones not signed
|
||||
(or not solely signed) using the new algorithm identifiers.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 10]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
8. Security Considerations
|
||||
|
||||
Zones using this methodology will be considered insecure by all
|
||||
resolvers except those aware of the experiment. It is not generally
|
||||
possible to create a secure delegation from an experimental zone that
|
||||
will be followed by resolvers unaware of the experiment.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 11]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
9. IANA Considerations
|
||||
|
||||
This document has no IANA actions.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 12]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
10. References
|
||||
|
||||
10.1. Normative References
|
||||
|
||||
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
|
||||
Levels", BCP 14, RFC 2119, March 1997.
|
||||
|
||||
[2] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
|
||||
"DNS Security Introduction and Requirements", RFC 4033,
|
||||
March 2005.
|
||||
|
||||
[3] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
|
||||
"Resource Records for the DNS Security Extensions", RFC 4034,
|
||||
March 2005.
|
||||
|
||||
[4] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
|
||||
"Protocol Modifications for the DNS Security Extensions",
|
||||
RFC 4035, March 2005.
|
||||
|
||||
10.2. Informative References
|
||||
|
||||
[5] Mockapetris, P., "Domain names - implementation and
|
||||
specification", STD 13, RFC 1035, November 1987.
|
||||
|
||||
[6] Austein, R. and S. Weiler, "Clarifications and Implementation
|
||||
Notes for DNSSECbis", draft-ietf-dnsext-dnssec-bis-updates-02
|
||||
(work in progress), January 2006.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 13]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
Author's Address
|
||||
|
||||
David Blacka
|
||||
VeriSign, Inc.
|
||||
21355 Ridgetop Circle
|
||||
Dulles, VA 20166
|
||||
US
|
||||
|
||||
Phone: +1 703 948 3200
|
||||
Email: davidb@verisign.com
|
||||
URI: http://www.verisignlabs.com
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 14]
|
||||
|
||||
Internet-Draft DNSSEC Experiments April 2006
|
||||
|
||||
|
||||
Full Copyright Statement
|
||||
|
||||
Copyright (C) The Internet Society (2006).
|
||||
|
||||
This document is subject to the rights, licenses and restrictions
|
||||
contained in BCP 78, and except as set forth therein, the authors
|
||||
retain all their rights.
|
||||
|
||||
This document and the information contained herein are provided on an
|
||||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
|
||||
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
|
||||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
|
||||
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
|
||||
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
|
||||
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
||||
|
||||
|
||||
Intellectual Property
|
||||
|
||||
The IETF takes no position regarding the validity or scope of any
|
||||
Intellectual Property Rights or other rights that might be claimed to
|
||||
pertain to the implementation or use of the technology described in
|
||||
this document or the extent to which any license under such rights
|
||||
might or might not be available; nor does it represent that it has
|
||||
made any independent effort to identify any such rights. Information
|
||||
on the procedures with respect to rights in RFC documents can be
|
||||
found in BCP 78 and BCP 79.
|
||||
|
||||
Copies of IPR disclosures made to the IETF Secretariat and any
|
||||
assurances of licenses to be made available, or the result of an
|
||||
attempt made to obtain a general license or permission for the use of
|
||||
such proprietary rights by implementers or users of this
|
||||
specification can be obtained from the IETF on-line IPR repository at
|
||||
http://www.ietf.org/ipr.
|
||||
|
||||
The IETF invites any interested party to bring to its attention any
|
||||
copyrights, patents or patent applications, or other proprietary
|
||||
rights that may cover technology that may be required to implement
|
||||
this standard. Please address the information to the IETF at
|
||||
ietf-ipr@ietf.org.
|
||||
|
||||
|
||||
Acknowledgment
|
||||
|
||||
Funding for the RFC Editor function is provided by the IETF
|
||||
Administrative Support Activity (IASA).
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Blacka Expires October 9, 2006 [Page 15]
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
@@ -1,464 +0,0 @@
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
OBSOLETES: RFC 2536 Donald E. Eastlake 3rd
|
||||
Motorola Laboratories
|
||||
Expires: September 2006 March 2006
|
||||
|
||||
|
||||
DSA Keying and Signature Information in the DNS
|
||||
--- ------ --- --------- ----------- -- --- ---
|
||||
<draft-ietf-dnsext-rfc2536bis-dsa-07.txt>
|
||||
Donald E. Eastlake 3rd
|
||||
|
||||
|
||||
Status of This Document
|
||||
|
||||
By submitting this Internet-Draft, each author represents that any
|
||||
applicable patent or other IPR claims of which he or she is aware
|
||||
have been or will be disclosed, and any of which he or she becomes
|
||||
aware will be disclosed, in accordance with Section 6 of BCP 79.
|
||||
|
||||
Distribution of this document is unlimited. Comments should be sent
|
||||
to the DNS extensions working group mailing list
|
||||
<namedroppers@ops.ietf.org>.
|
||||
|
||||
Internet-Drafts are working documents of the Internet Engineering
|
||||
Task Force (IETF), its areas, and its working groups. Note that
|
||||
other groups may also distribute working documents as Internet-
|
||||
Drafts.
|
||||
|
||||
Internet-Drafts are draft documents valid for a maximum of six months
|
||||
and may be updated, replaced, or obsoleted by other documents at any
|
||||
time. It is inappropriate to use Internet-Drafts as reference
|
||||
material or to cite them other than as "work in progress."
|
||||
|
||||
The list of current Internet-Drafts can be accessed at
|
||||
http://www.ietf.org/1id-abstracts.html
|
||||
|
||||
The list of Internet-Draft Shadow Directories can be accessed at
|
||||
http://www.ietf.org/shadow.html
|
||||
|
||||
|
||||
|
||||
Abstract
|
||||
|
||||
The standard method of encoding US Government Digital Signature
|
||||
Algorithm keying and signature information for use in the Domain Name
|
||||
System is specified.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 1]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
Table of Contents
|
||||
|
||||
Status of This Document....................................1
|
||||
Abstract...................................................1
|
||||
|
||||
Table of Contents..........................................2
|
||||
|
||||
1. Introduction............................................3
|
||||
2. DSA Keying Information..................................3
|
||||
3. DSA Signature Information...............................4
|
||||
4. Performance Considerations..............................4
|
||||
5. Security Considerations.................................5
|
||||
6. IANA Considerations.....................................5
|
||||
Copyright, Disclaimer, and Additional IPR Provisions.......5
|
||||
|
||||
Normative References.......................................7
|
||||
Informative References.....................................7
|
||||
|
||||
Author's Address...........................................8
|
||||
Expiration and File Name...................................8
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 2]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
1. Introduction
|
||||
|
||||
The Domain Name System (DNS) is the global hierarchical replicated
|
||||
distributed database system for Internet addressing, mail proxy, and
|
||||
other information [RFC 1034, 1035]. The DNS has been extended to
|
||||
include digital signatures and cryptographic keys as described in
|
||||
[RFC 4033, 4034, 4035] and additional work is underway which would
|
||||
require the storage of keying and signature information in the DNS.
|
||||
|
||||
This document describes how to encode US Government Digital Signature
|
||||
Algorithm (DSA) keys and signatures in the DNS. Familiarity with the
|
||||
US Digital Signature Algorithm is assumed [FIPS 186-2, Schneier].
|
||||
|
||||
|
||||
|
||||
2. DSA Keying Information
|
||||
|
||||
When DSA public keys are stored in the DNS, the structure of the
|
||||
relevant part of the RDATA part of the RR being used is the fields
|
||||
listed below in the order given.
|
||||
|
||||
The period of key validity is not included in this data but is
|
||||
indicated separately, for example by an RR such as RRSIG which signs
|
||||
and authenticates the RR containing the keying information.
|
||||
|
||||
Field Size
|
||||
----- ----
|
||||
T 1 octet
|
||||
Q 20 octets
|
||||
P 64 + T*8 octets
|
||||
G 64 + T*8 octets
|
||||
Y 64 + T*8 octets
|
||||
|
||||
As described in [FIPS 186-2] and [Schneier], T is a key size
|
||||
parameter chosen such that 0 <= T <= 8. (The meaning if the T octet
|
||||
is greater than 8 is reserved and the remainder of the data may have
|
||||
a different format in that case.) Q is a prime number selected at
|
||||
key generation time such that 2**159 < Q < 2**160. Thus Q is always
|
||||
20 octets long and, as with all other fields, is stored in "big-
|
||||
endian" network order. P, G, and Y are calculated as directed by the
|
||||
[FIPS 186-2] key generation algorithm [Schneier]. P is in the range
|
||||
2**(511+64T) < P < 2**(512+64T) and thus is 64 + 8*T octets long. G
|
||||
and Y are quantities modulo P and so can be up to the same length as
|
||||
P and are allocated fixed size fields with the same number of octets
|
||||
as P.
|
||||
|
||||
During the key generation process, a random number X must be
|
||||
generated such that 1 <= X <= Q-1. X is the private key and is used
|
||||
in the final step of public key generation where Y is computed as
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 3]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
Y = G**X mod P
|
||||
|
||||
|
||||
|
||||
3. DSA Signature Information
|
||||
|
||||
The portion of the RDATA area used for US Digital Signature Algorithm
|
||||
signature information is shown below with fields in the order they
|
||||
are listed and the contents of each multi-octet field in "big-endian"
|
||||
network order.
|
||||
|
||||
Field Size
|
||||
----- ----
|
||||
T 1 octet
|
||||
R 20 octets
|
||||
S 20 octets
|
||||
|
||||
First, the data signed must be determined. Then the following steps
|
||||
are taken, as specified in [FIPS 186-2], where Q, P, G, and Y are as
|
||||
specified in the public key [Schneier]:
|
||||
|
||||
hash = SHA-1 ( data )
|
||||
|
||||
Generate a random K such that 0 < K < Q.
|
||||
|
||||
R = ( G**K mod P ) mod Q
|
||||
|
||||
S = ( K**(-1) * (hash + X*R) ) mod Q
|
||||
|
||||
For information on the SHA-1 hash function see [FIPS 180-2] and [RFC
|
||||
3174].
|
||||
|
||||
Since Q is 160 bits long, R and S can not be larger than 20 octets,
|
||||
which is the space allocated.
|
||||
|
||||
T is copied from the public key. It is not logically necessary in
|
||||
the SIG but is present so that values of T > 8 can more conveniently
|
||||
be used as an escape for extended versions of DSA or other algorithms
|
||||
as later standardized.
|
||||
|
||||
|
||||
|
||||
4. Performance Considerations
|
||||
|
||||
General signature generation speeds are roughly the same for RSA [RFC
|
||||
3110] and DSA. With sufficient pre-computation, signature generation
|
||||
with DSA is faster than RSA. Key generation is also faster for DSA.
|
||||
However, signature verification is an order of magnitude slower than
|
||||
RSA when the RSA public exponent is chosen to be small, as is
|
||||
recommended for some applications.
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 4]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
Current DNS implementations are optimized for small transfers,
|
||||
typically less than 512 bytes including DNS overhead. Larger
|
||||
transfers will perform correctly and extensions have been
|
||||
standardized [RFC 2671] to make larger transfers more efficient, it
|
||||
is still advisable at this time to make reasonable efforts to
|
||||
minimize the size of RR sets containing keying and/or signature
|
||||
inforamtion consistent with adequate security.
|
||||
|
||||
|
||||
|
||||
5. Security Considerations
|
||||
|
||||
Keys retrieved from the DNS should not be trusted unless (1) they
|
||||
have been securely obtained from a secure resolver or independently
|
||||
verified by the user and (2) this secure resolver and secure
|
||||
obtainment or independent verification conform to security policies
|
||||
acceptable to the user. As with all cryptographic algorithms,
|
||||
evaluating the necessary strength of the key is essential and
|
||||
dependent on local policy.
|
||||
|
||||
The key size limitation of a maximum of 1024 bits ( T = 8 ) in the
|
||||
current DSA standard may limit the security of DSA. For particular
|
||||
applications, implementors are encouraged to consider the range of
|
||||
available algorithms and key sizes.
|
||||
|
||||
DSA assumes the ability to frequently generate high quality random
|
||||
numbers. See [random] for guidance. DSA is designed so that if
|
||||
biased rather than random numbers are used, high bandwidth covert
|
||||
channels are possible. See [Schneier] and more recent research. The
|
||||
leakage of an entire DSA private key in only two DSA signatures has
|
||||
been demonstrated. DSA provides security only if trusted
|
||||
implementations, including trusted random number generation, are
|
||||
used.
|
||||
|
||||
|
||||
|
||||
6. IANA Considerations
|
||||
|
||||
Allocation of meaning to values of the T parameter that are not
|
||||
defined herein (i.e., > 8 ) requires an IETF standards actions. It
|
||||
is intended that values unallocated herein be used to cover future
|
||||
extensions of the DSS standard.
|
||||
|
||||
|
||||
|
||||
Copyright, Disclaimer, and Additional IPR Provisions
|
||||
|
||||
Copyright (C) The Internet Society (2006). This document is subject to
|
||||
the rights, licenses and restrictions contained in BCP 78, and except
|
||||
as set forth therein, the authors retain all their rights.
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 5]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
This document and the information contained herein are provided on an
|
||||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
|
||||
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
|
||||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
|
||||
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
|
||||
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
|
||||
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
||||
|
||||
The IETF takes no position regarding the validity or scope of any
|
||||
Intellectual Property Rights or other rights that might be claimed to
|
||||
pertain to the implementation or use of the technology described in
|
||||
this document or the extent to which any license under such rights
|
||||
might or might not be available; nor does it represent that it has
|
||||
made any independent effort to identify any such rights. Information
|
||||
on the procedures with respect to rights in RFC documents can be
|
||||
found in BCP 78 and BCP 79.
|
||||
|
||||
Copies of IPR disclosures made to the IETF Secretariat and any
|
||||
assurances of licenses to be made available, or the result of an
|
||||
attempt made to obtain a general license or permission for the use of
|
||||
such proprietary rights by implementers or users of this
|
||||
specification can be obtained from the IETF on-line IPR repository at
|
||||
http://www.ietf.org/ipr.
|
||||
|
||||
The IETF invites any interested party to bring to its attention any
|
||||
copyrights, patents or patent applications, or other proprietary
|
||||
rights that may cover technology that may be required to implement
|
||||
this standard. Please address the information to the IETF at ietf-
|
||||
ipr@ietf.org.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 6]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
Normative References
|
||||
|
||||
[FIPS 186-2] - U.S. Federal Information Processing Standard: Digital
|
||||
Signature Standard, 27 January 2000.
|
||||
|
||||
[RFC 4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Resource Records for the DNS Security Extensions", RFC 4034,
|
||||
March 2005.
|
||||
|
||||
|
||||
|
||||
Informative References
|
||||
|
||||
[RFC 1034] - "Domain names - concepts and facilities", P.
|
||||
Mockapetris, 11/01/1987.
|
||||
|
||||
[RFC 1035] - "Domain names - implementation and specification", P.
|
||||
Mockapetris, 11/01/1987.
|
||||
|
||||
[RFC 2671] - "Extension Mechanisms for DNS (EDNS0)", P. Vixie, August
|
||||
1999.
|
||||
|
||||
[RFC 3110] - "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System
|
||||
(DNS)", D. Eastlake 3rd. May 2001.
|
||||
|
||||
[RFC 3174] - "US Secure Hash Algorithm 1 (SHA1)", D. Eastlake, P.
|
||||
Jones, September 2001.
|
||||
|
||||
[RFC 4033] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "DNS Security Introduction and Requirements", RFC 4033, March
|
||||
2005.
|
||||
|
||||
[RFC 4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Protocol Modifications for the DNS Security Extensions", RFC
|
||||
4035, March 2005.
|
||||
|
||||
[RFC 4086] - Eastlake, D., 3rd, Schiller, J., and S. Crocker,
|
||||
"Randomness Requirements for Security", BCP 106, RFC 4086, June 2005.
|
||||
|
||||
[Schneier] - "Applied Cryptography Second Edition: protocols,
|
||||
algorithms, and source code in C" (second edition), Bruce Schneier,
|
||||
1996, John Wiley and Sons, ISBN 0-471-11709-9.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 7]
|
||||
|
||||
|
||||
INTERNET-DRAFT DSA Information in the DNS
|
||||
|
||||
|
||||
Author's Address
|
||||
|
||||
Donald E. Eastlake 3rd
|
||||
Motorola Labortories
|
||||
155 Beaver Street
|
||||
Milford, MA 01757 USA
|
||||
|
||||
Telephone: +1-508-786-7554(w)
|
||||
EMail: Donald.Eastlake@motorola.com
|
||||
|
||||
|
||||
|
||||
Expiration and File Name
|
||||
|
||||
This draft expires in September 2006.
|
||||
|
||||
Its file name is draft-ietf-dnsext-rfc2536bis-dsa-07.txt.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 8]
|
||||
|
||||
@@ -1,580 +0,0 @@
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
OBSOLETES: RFC 2539 Donald E. Eastlake 3rd
|
||||
Motorola Laboratories
|
||||
Expires: September 2006 March 2006
|
||||
|
||||
|
||||
|
||||
|
||||
Storage of Diffie-Hellman Keying Information in the DNS
|
||||
------- -- -------------- ------ ----------- -- --- ---
|
||||
<draft-ietf-dnsext-rfc2539bis-dhk-07.txt>
|
||||
|
||||
|
||||
|
||||
Status of This Document
|
||||
|
||||
By submitting this Internet-Draft, each author represents that any
|
||||
applicable patent or other IPR claims of which he or she is aware
|
||||
have been or will be disclosed, and any of which he or she becomes
|
||||
aware will be disclosed, in accordance with Section 6 of BCP 79.
|
||||
|
||||
Distribution of this document is unlimited. Comments should be sent
|
||||
to the DNS extensions working group mailing list
|
||||
<namedroppers@ops.ietf.org>.
|
||||
|
||||
Internet-Drafts are working documents of the Internet Engineering
|
||||
Task Force (IETF), its areas, and its working groups. Note that
|
||||
other groups may also distribute working documents as Internet-
|
||||
Drafts.
|
||||
|
||||
Internet-Drafts are draft documents valid for a maximum of six months
|
||||
and may be updated, replaced, or obsoleted by other documents at any
|
||||
time. It is inappropriate to use Internet-Drafts as reference
|
||||
material or to cite them other than as "work in progress."
|
||||
|
||||
The list of current Internet-Drafts can be accessed at
|
||||
http://www.ietf.org/1id-abstracts.html
|
||||
|
||||
The list of Internet-Draft Shadow Directories can be accessed at
|
||||
http://www.ietf.org/shadow.html
|
||||
|
||||
|
||||
Abstract
|
||||
|
||||
The standard method for encoding Diffie-Hellman keys in the Domain
|
||||
Name System is specified.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 1]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
Acknowledgements
|
||||
|
||||
Part of the format for Diffie-Hellman keys and the description
|
||||
thereof was taken from a work in progress by Ashar Aziz, Tom Markson,
|
||||
and Hemma Prafullchandra. In addition, the following persons
|
||||
provided useful comments that were incorporated into the predecessor
|
||||
of this document: Ran Atkinson, Thomas Narten.
|
||||
|
||||
|
||||
|
||||
Table of Contents
|
||||
|
||||
Status of This Document....................................1
|
||||
Abstract...................................................1
|
||||
|
||||
Acknowledgements...........................................2
|
||||
Table of Contents..........................................2
|
||||
|
||||
1. Introduction............................................3
|
||||
1.1 About This Document....................................3
|
||||
1.2 About Diffie-Hellman...................................3
|
||||
2. Encoding Diffie-Hellman Keying Information..............4
|
||||
3. Performance Considerations..............................5
|
||||
4. IANA Considerations.....................................5
|
||||
5. Security Considerations.................................5
|
||||
Copyright, Disclaimer, and Additional IPR Provisions.......5
|
||||
|
||||
Normative References.......................................7
|
||||
Informative Refences.......................................7
|
||||
|
||||
Author's Address...........................................8
|
||||
Expiration and File Name...................................8
|
||||
|
||||
Appendix A: Well known prime/generator pairs...............9
|
||||
A.1. Well-Known Group 1: A 768 bit prime..................9
|
||||
A.2. Well-Known Group 2: A 1024 bit prime.................9
|
||||
A.3. Well-Known Group 3: A 1536 bit prime................10
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 2]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
1. Introduction
|
||||
|
||||
The Domain Name System (DNS) is the global hierarchical replicated
|
||||
distributed database system for Internet addressing, mail proxy, and
|
||||
similar information [RFC 1034, 1035]. The DNS has been extended to
|
||||
include digital signatures and cryptographic keys as described in
|
||||
[RFC 4033, 4034, 4035] and additonal work is underway which would use
|
||||
the storage of keying information in the DNS.
|
||||
|
||||
|
||||
|
||||
1.1 About This Document
|
||||
|
||||
This document describes how to store Diffie-Hellman keys in the DNS.
|
||||
Familiarity with the Diffie-Hellman key exchange algorithm is assumed
|
||||
[Schneier, RFC 2631].
|
||||
|
||||
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
|
||||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
|
||||
document are to be interpreted as described in RFC 2119.
|
||||
|
||||
|
||||
|
||||
1.2 About Diffie-Hellman
|
||||
|
||||
Diffie-Hellman requires two parties to interact to derive keying
|
||||
information which can then be used for authentication. Thus Diffie-
|
||||
Hellman is inherently a key agreement algorithm. As a result, no
|
||||
format is defined for Diffie-Hellman "signature information". For
|
||||
example, assume that two parties have local secrets "i" and "j".
|
||||
Assume they each respectively calculate X and Y as follows:
|
||||
|
||||
X = g**i ( mod p )
|
||||
|
||||
Y = g**j ( mod p )
|
||||
|
||||
They exchange these quantities and then each calculates a Z as
|
||||
follows:
|
||||
|
||||
Zi = Y**i ( mod p )
|
||||
|
||||
Zj = X**j ( mod p )
|
||||
|
||||
Zi and Zj will both be equal to g**(i*j)(mod p) and will be a shared
|
||||
secret between the two parties that an adversary who does not know i
|
||||
or j will not be able to learn from the exchanged messages (unless
|
||||
the adversary can derive i or j by performing a discrete logarithm
|
||||
mod p which is hard for strong p and g).
|
||||
|
||||
The private key for each party is their secret i (or j). The public
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 3]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
key is the pair p and g, which is the same for both parties, and
|
||||
their individual X (or Y).
|
||||
|
||||
For further information about Diffie-Hellman and precautions to take
|
||||
in deciding on a p and g, see [RFC 2631].
|
||||
|
||||
|
||||
|
||||
2. Encoding Diffie-Hellman Keying Information
|
||||
|
||||
When Diffie-Hellman keys appear within the RDATA portion of a RR,
|
||||
they are encoded as shown below.
|
||||
|
||||
The period of key validity is not included in this data but is
|
||||
indicated separately, for example by an RR such as RRSIG which signs
|
||||
and authenticates the RR containing the keying information.
|
||||
|
||||
1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
|
||||
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
| KEY flags | protocol | algorithm=2 |
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
| prime length (or flag) | prime (p) (or special) /
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
/ prime (p) (variable length) | generator length |
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
| generator (g) (variable length) |
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
| public value length | public value (variable length)/
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
/ public value (g^i mod p) (variable length) |
|
||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
|
||||
Prime length is the length of the Diffie-Hellman prime (p) in bytes
|
||||
if it is 16 or greater. Prime contains the binary representation of
|
||||
the Diffie-Hellman prime with most significant byte first (i.e., in
|
||||
network order). If "prime length" field is 1 or 2, then the "prime"
|
||||
field is actually an unsigned index into a table of 65,536
|
||||
prime/generator pairs and the generator length SHOULD be zero. See
|
||||
Appedix A for defined table entries and Section 4 for information on
|
||||
allocating additional table entries. The meaning of a zero or 3
|
||||
through 15 value for "prime length" is reserved.
|
||||
|
||||
Generator length is the length of the generator (g) in bytes.
|
||||
Generator is the binary representation of generator with most
|
||||
significant byte first. PublicValueLen is the Length of the Public
|
||||
Value (g**i (mod p)) in bytes. PublicValue is the binary
|
||||
representation of the DH public value with most significant byte
|
||||
first.
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 4]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
3. Performance Considerations
|
||||
|
||||
Current DNS implementations are optimized for small transfers,
|
||||
typically less than 512 bytes including DNS overhead. Larger
|
||||
transfers will perform correctly and extensions have been
|
||||
standardized [RFC 2671] to make larger transfers more efficient. But
|
||||
it is still advisable at this time to make reasonable efforts to
|
||||
minimize the size of RR sets containing keying information consistent
|
||||
with adequate security.
|
||||
|
||||
|
||||
|
||||
4. IANA Considerations
|
||||
|
||||
Assignment of meaning to Prime Lengths of 0 and 3 through 15 requires
|
||||
an IETF consensus as defined in [RFC 2434].
|
||||
|
||||
Well known prime/generator pairs number 0x0000 through 0x07FF can
|
||||
only be assigned by an IETF standards action. [RFC 2539], the
|
||||
Proposed Standard predecessor of this document, assigned 0x0001
|
||||
through 0x0002. This document additionally assigns 0x0003. Pairs
|
||||
number 0s0800 through 0xBFFF can be assigned based on RFC
|
||||
documentation. Pairs number 0xC000 through 0xFFFF are available for
|
||||
private use and are not centrally coordinated. Use of such private
|
||||
pairs outside of a closed environment may result in conflicts and/or
|
||||
security failures.
|
||||
|
||||
|
||||
|
||||
5. Security Considerations
|
||||
|
||||
Keying information retrieved from the DNS should not be trusted
|
||||
unless (1) it has been securely obtained from a secure resolver or
|
||||
independently verified by the user and (2) this secure resolver and
|
||||
secure obtainment or independent verification conform to security
|
||||
policies acceptable to the user. As with all cryptographic
|
||||
algorithms, evaluating the necessary strength of the key is important
|
||||
and dependent on security policy.
|
||||
|
||||
In addition, the usual Diffie-Hellman key strength considerations
|
||||
apply. (p-1)/2 SHOULD also be prime, g SHOULD be primitive mod p, p
|
||||
SHOULD be "large", etc. See [RFC 2631, Schneier].
|
||||
|
||||
|
||||
|
||||
Copyright, Disclaimer, and Additional IPR Provisions
|
||||
|
||||
Copyright (C) The Internet Society (2006). This document is subject to
|
||||
the rights, licenses and restrictions contained in BCP 78, and except
|
||||
as set forth therein, the authors retain all their rights.
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 5]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
This document and the information contained herein are provided on an
|
||||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
|
||||
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
|
||||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
|
||||
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
|
||||
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
|
||||
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
||||
|
||||
The IETF takes no position regarding the validity or scope of any
|
||||
Intellectual Property Rights or other rights that might be claimed to
|
||||
pertain to the implementation or use of the technology described in
|
||||
this document or the extent to which any license under such rights
|
||||
might or might not be available; nor does it represent that it has
|
||||
made any independent effort to identify any such rights. Information
|
||||
on the procedures with respect to rights in RFC documents can be
|
||||
found in BCP 78 and BCP 79.
|
||||
|
||||
Copies of IPR disclosures made to the IETF Secretariat and any
|
||||
assurances of licenses to be made available, or the result of an
|
||||
attempt made to obtain a general license or permission for the use of
|
||||
such proprietary rights by implementers or users of this
|
||||
specification can be obtained from the IETF on-line IPR repository at
|
||||
http://www.ietf.org/ipr.
|
||||
|
||||
The IETF invites any interested party to bring to its attention any
|
||||
copyrights, patents or patent applications, or other proprietary
|
||||
rights that may cover technology that may be required to implement
|
||||
this standard. Please address the information to the IETF at ietf-
|
||||
ipr@ietf.org.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 6]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
Normative References
|
||||
|
||||
[RFC 2119] - Bradner, S., "Key words for use in RFCs to Indicate
|
||||
Requirement Levels", BCP 14, RFC 2119, March 1997.
|
||||
|
||||
[RFC 2434] - "Guidelines for Writing an IANA Considerations Section
|
||||
in RFCs", T. Narten, H. Alvestrand, October 1998.
|
||||
|
||||
[RFC 2631] - "Diffie-Hellman Key Agreement Method", E. Rescorla, June
|
||||
1999.
|
||||
|
||||
[RFC 4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Resource Records for the DNS Security Extensions", RFC 4034,
|
||||
March 2005.
|
||||
|
||||
|
||||
|
||||
Informative Refences
|
||||
|
||||
[RFC 1034] - "Domain names - concepts and facilities", P.
|
||||
Mockapetris, November 1987.
|
||||
|
||||
[RFC 1035] - "Domain names - implementation and specification", P.
|
||||
Mockapetris, November 1987.
|
||||
|
||||
[RFC 2539] - "Storage of Diffie-Hellman Keys in the Domain Name
|
||||
System (DNS)", D. Eastlake, March 1999, obsoleted by this RFC.
|
||||
|
||||
[RFC 2671] - "Extension Mechanisms for DNS (EDNS0)", P. Vixie, August
|
||||
1999.
|
||||
|
||||
[RFC 4033] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "DNS Security Introduction and Requirements", RFC 4033, March
|
||||
2005.
|
||||
|
||||
[RFC 4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Protocol Modifications for the DNS Security Extensions", RFC
|
||||
4035, March 2005.
|
||||
|
||||
[Schneier] - Bruce Schneier, "Applied Cryptography: Protocols,
|
||||
Algorithms, and Source Code in C" (Second Edition), 1996, John Wiley
|
||||
and Sons.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 7]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
Author's Address
|
||||
|
||||
Donald E. Eastlake 3rd
|
||||
Motorola Laboratories
|
||||
155 Beaver Street
|
||||
Milford, MA 01757 USA
|
||||
|
||||
Telephone: +1-508-786-7554
|
||||
EMail: Donald.Eastlake@motorola.com
|
||||
|
||||
|
||||
|
||||
Expiration and File Name
|
||||
|
||||
This draft expires in September 2006.
|
||||
|
||||
Its file name is draft-ietf-dnsext-rfc2539bis-dhk-07.txt.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 8]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
Appendix A: Well known prime/generator pairs
|
||||
|
||||
These numbers are copied from the IPSEC effort where the derivation
|
||||
of these values is more fully explained and additional information is
|
||||
available. Richard Schroeppel performed all the mathematical and
|
||||
computational work for this appendix.
|
||||
|
||||
|
||||
|
||||
A.1. Well-Known Group 1: A 768 bit prime
|
||||
|
||||
The prime is 2^768 - 2^704 - 1 + 2^64 * { [2^638 pi] + 149686 }. Its
|
||||
decimal value is
|
||||
155251809230070893513091813125848175563133404943451431320235
|
||||
119490296623994910210725866945387659164244291000768028886422
|
||||
915080371891804634263272761303128298374438082089019628850917
|
||||
0691316593175367469551763119843371637221007210577919
|
||||
|
||||
Prime modulus: Length (32 bit words): 24, Data (hex):
|
||||
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
|
||||
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
|
||||
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
|
||||
E485B576 625E7EC6 F44C42E9 A63A3620 FFFFFFFF FFFFFFFF
|
||||
|
||||
Generator: Length (32 bit words): 1, Data (hex): 2
|
||||
|
||||
|
||||
|
||||
A.2. Well-Known Group 2: A 1024 bit prime
|
||||
|
||||
The prime is 2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }.
|
||||
Its decimal value is
|
||||
179769313486231590770839156793787453197860296048756011706444
|
||||
423684197180216158519368947833795864925541502180565485980503
|
||||
646440548199239100050792877003355816639229553136239076508735
|
||||
759914822574862575007425302077447712589550957937778424442426
|
||||
617334727629299387668709205606050270810842907692932019128194
|
||||
467627007
|
||||
|
||||
Prime modulus: Length (32 bit words): 32, Data (hex):
|
||||
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
|
||||
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
|
||||
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
|
||||
E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
|
||||
EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE65381
|
||||
FFFFFFFF FFFFFFFF
|
||||
|
||||
Generator: Length (32 bit words): 1, Data (hex): 2
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 9]
|
||||
|
||||
|
||||
INTERNET-DRAFT Diffie-Hellman Information in the DNS
|
||||
|
||||
|
||||
A.3. Well-Known Group 3: A 1536 bit prime
|
||||
|
||||
The prime is 2^1536 - 2^1472 - 1 + 2^64 * { [2^1406 pi] + 741804 }.
|
||||
Its decimal value is
|
||||
241031242692103258855207602219756607485695054850245994265411
|
||||
694195810883168261222889009385826134161467322714147790401219
|
||||
650364895705058263194273070680500922306273474534107340669624
|
||||
601458936165977404102716924945320037872943417032584377865919
|
||||
814376319377685986952408894019557734611984354530154704374720
|
||||
774996976375008430892633929555996888245787241299381012913029
|
||||
459299994792636526405928464720973038494721168143446471443848
|
||||
8520940127459844288859336526896320919633919
|
||||
|
||||
Prime modulus Length (32 bit words): 48, Data (hex):
|
||||
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
|
||||
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
|
||||
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
|
||||
E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
|
||||
EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D
|
||||
C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F
|
||||
83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
|
||||
670C354E 4ABC9804 F1746C08 CA237327 FFFFFFFF FFFFFFFF
|
||||
|
||||
Generator: Length (32 bit words): 1, Data (hex): 2
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
D. Eastlake 3rd [Page 10]
|
||||
|
||||
@@ -1,729 +0,0 @@
|
||||
|
||||
|
||||
|
||||
Network Working Group M. StJohns
|
||||
Internet-Draft Nominum, Inc.
|
||||
Intended status: Informational November 29, 2006
|
||||
Expires: June 2, 2007
|
||||
|
||||
|
||||
Automated Updates of DNSSEC Trust Anchors
|
||||
draft-ietf-dnsext-trustupdate-timers-05
|
||||
|
||||
Status of this Memo
|
||||
|
||||
By submitting this Internet-Draft, each author represents that any
|
||||
applicable patent or other IPR claims of which he or she is aware
|
||||
have been or will be disclosed, and any of which he or she becomes
|
||||
aware will be disclosed, in accordance with Section 6 of BCP 79.
|
||||
|
||||
Internet-Drafts are working documents of the Internet Engineering
|
||||
Task Force (IETF), its areas, and its working groups. Note that
|
||||
other groups may also distribute working documents as Internet-
|
||||
Drafts.
|
||||
|
||||
Internet-Drafts are draft documents valid for a maximum of six months
|
||||
and may be updated, replaced, or obsoleted by other documents at any
|
||||
time. It is inappropriate to use Internet-Drafts as reference
|
||||
material or to cite them other than as "work in progress."
|
||||
|
||||
The list of current Internet-Drafts can be accessed at
|
||||
http://www.ietf.org/ietf/1id-abstracts.txt.
|
||||
|
||||
The list of Internet-Draft Shadow Directories can be accessed at
|
||||
http://www.ietf.org/shadow.html.
|
||||
|
||||
This Internet-Draft will expire on June 2, 2007.
|
||||
|
||||
Copyright Notice
|
||||
|
||||
Copyright (C) The Internet Society (2006).
|
||||
|
||||
Abstract
|
||||
|
||||
This document describes a means for automated, authenticated and
|
||||
authorized updating of DNSSEC "trust anchors". The method provides
|
||||
protection against N-1 key compromises of N keys in the trust point
|
||||
key set. Based on the trust established by the presence of a current
|
||||
anchor, other anchors may be added at the same place in the
|
||||
hierarchy, and, ultimately, supplant the existing anchor(s).
|
||||
|
||||
This mechanism will require changes to resolver management behavior
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 1]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
(but not resolver resolution behavior), and the addition of a single
|
||||
flag bit to the DNSKEY record.
|
||||
|
||||
|
||||
Table of Contents
|
||||
|
||||
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
|
||||
1.1. Compliance Nomenclature . . . . . . . . . . . . . . . . . 3
|
||||
2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 4
|
||||
2.1. Revocation . . . . . . . . . . . . . . . . . . . . . . . . 4
|
||||
2.2. Add Hold-Down . . . . . . . . . . . . . . . . . . . . . . 5
|
||||
2.3. Active Refresh . . . . . . . . . . . . . . . . . . . . . . 5
|
||||
2.4. Resolver Parameters . . . . . . . . . . . . . . . . . . . 6
|
||||
2.4.1. Add Hold-Down Time . . . . . . . . . . . . . . . . . . 6
|
||||
2.4.2. Remove Hold-Down Time . . . . . . . . . . . . . . . . 6
|
||||
2.4.3. Minimum Trust Anchors per Trust Point . . . . . . . . 6
|
||||
3. Changes to DNSKEY RDATA Wire Format . . . . . . . . . . . . . 6
|
||||
4. State Table . . . . . . . . . . . . . . . . . . . . . . . . . 6
|
||||
4.1. Events . . . . . . . . . . . . . . . . . . . . . . . . . . 7
|
||||
4.2. States . . . . . . . . . . . . . . . . . . . . . . . . . . 8
|
||||
5. Trust Point Deletion . . . . . . . . . . . . . . . . . . . . . 8
|
||||
6. Scenarios - Informative . . . . . . . . . . . . . . . . . . . 9
|
||||
6.1. Adding a Trust Anchor . . . . . . . . . . . . . . . . . . 9
|
||||
6.2. Deleting a Trust Anchor . . . . . . . . . . . . . . . . . 9
|
||||
6.3. Key Roll-Over . . . . . . . . . . . . . . . . . . . . . . 10
|
||||
6.4. Active Key Compromised . . . . . . . . . . . . . . . . . . 10
|
||||
6.5. Stand-by Key Compromised . . . . . . . . . . . . . . . . . 10
|
||||
6.6. Trust Point Deletion . . . . . . . . . . . . . . . . . . . 10
|
||||
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
|
||||
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
|
||||
8.1. Key Ownership vs Acceptance Policy . . . . . . . . . . . . 11
|
||||
8.2. Multiple Key Compromise . . . . . . . . . . . . . . . . . 11
|
||||
8.3. Dynamic Updates . . . . . . . . . . . . . . . . . . . . . 11
|
||||
9. Normative References . . . . . . . . . . . . . . . . . . . . . 12
|
||||
Editorial Comments . . . . . . . . . . . . . . . . . . . . . . . .
|
||||
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 12
|
||||
Intellectual Property and Copyright Statements . . . . . . . . . . 13
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 2]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
1. Introduction
|
||||
|
||||
As part of the reality of fielding DNSSEC (Domain Name System
|
||||
Security Extensions) [RFC4033] [RFC4034] [RFC4035], the community has
|
||||
come to the realization that there will not be one signed name space,
|
||||
but rather islands of signed name space each originating from
|
||||
specific points (i.e. 'trust points') in the DNS tree. Each of those
|
||||
islands will be identified by the trust point name, and validated by
|
||||
at least one associated public key. For the purpose of this document
|
||||
we'll call the association of that name and a particular key a 'trust
|
||||
anchor'. A particular trust point can have more than one key
|
||||
designated as a trust anchor.
|
||||
|
||||
For a DNSSEC-aware resolver to validate information in a DNSSEC
|
||||
protected branch of the hierarchy, it must have knowledge of a trust
|
||||
anchor applicable to that branch. It may also have more than one
|
||||
trust anchor for any given trust point. Under current rules, a chain
|
||||
of trust for DNSSEC-protected data that chains its way back to ANY
|
||||
known trust anchor is considered 'secure'.
|
||||
|
||||
Because of the probable balkanization of the DNSSEC tree due to
|
||||
signing voids at key locations, a resolver may need to know literally
|
||||
thousands of trust anchors to perform its duties. (e.g. Consider an
|
||||
unsigned ".COM".) Requiring the owner of the resolver to manually
|
||||
manage this many relationships is problematic. It's even more
|
||||
problematic when considering the eventual requirement for key
|
||||
replacement/update for a given trust anchor. The mechanism described
|
||||
herein won't help with the initial configuration of the trust anchors
|
||||
in the resolvers, but should make trust point key replacement/
|
||||
rollover more viable.
|
||||
|
||||
As mentioned above, this document describes a mechanism whereby a
|
||||
resolver can update the trust anchors for a given trust point, mainly
|
||||
without human intervention at the resolver. There are some corner
|
||||
cases discussed (e.g. multiple key compromise) that may require
|
||||
manual intervention, but they should be few and far between. This
|
||||
document DOES NOT discuss the general problem of the initial
|
||||
configuration of trust anchors for the resolver.
|
||||
|
||||
1.1. Compliance Nomenclature
|
||||
|
||||
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
|
||||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
|
||||
document are to be interpreted as described in BCP 14, [RFC2119].
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 3]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
2. Theory of Operation
|
||||
|
||||
The general concept of this mechanism is that existing trust anchors
|
||||
can be used to authenticate new trust anchors at the same point in
|
||||
the DNS hierarchy. When a zone operator adds a new SEP key (i.e. a
|
||||
DNSKEY with the Secure Entry Point bit set) (see [RFC4034]section
|
||||
2.1.1) to a trust point DNSKEY RRSet, and when that RRSet is
|
||||
validated by an existing trust anchor, then the resolver can add the
|
||||
new key to its valid set of trust anchors for that trust point.
|
||||
|
||||
There are some issues with this approach which need to be mitigated.
|
||||
For example, a compromise of one of the existing keys could allow an
|
||||
attacker to add their own 'valid' data. This implies a need for a
|
||||
method to revoke an existing key regardless of whether or not that
|
||||
key is compromised. As another example, assuming a single key
|
||||
compromise, we need to prevent an attacker from adding a new key and
|
||||
revoking all the other old keys.
|
||||
|
||||
2.1. Revocation
|
||||
|
||||
Assume two trust anchor keys A and B. Assume that B has been
|
||||
compromised. Without a specific revocation bit, B could invalidate A
|
||||
simply by sending out a signed trust point key set which didn't
|
||||
contain A. To fix this, we add a mechanism which requires knowledge
|
||||
of the private key of a DNSKEY to revoke that DNSKEY.
|
||||
|
||||
A key is considered revoked when the resolver sees the key in a self-
|
||||
signed RRSet and the key has the REVOKE bit (see Section 7 below) set
|
||||
to '1'. Once the resolver sees the REVOKE bit, it MUST NOT use this
|
||||
key as a trust anchor or for any other purposes except validating the
|
||||
RRSIG it signed over the DNSKEY RRSet specifically for the purpose of
|
||||
validating the revocation. Unlike the 'Add' operation below,
|
||||
revocation is immediate and permanent upon receipt of a valid
|
||||
revocation at the resolver.
|
||||
|
||||
A self-signed RRSet is a DNSKEY RRSet which contains the specific
|
||||
DNSKEY and for which there is a corresponding validated RRSIG record.
|
||||
It's not a special DNSKEY RRSet, just a way of describing the
|
||||
validation requirements for that RRSet.
|
||||
|
||||
N.B. A DNSKEY with the REVOKE bit set has a different fingerprint
|
||||
than one without the bit set. This affects the matching of a DNSKEY
|
||||
to DS records in the parent, or the fingerprint stored at a resolver
|
||||
used to configure a trust point.
|
||||
|
||||
In the given example, the attacker could revoke B because it has
|
||||
knowledge of B's private key, but could not revoke A.
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 4]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
2.2. Add Hold-Down
|
||||
|
||||
Assume two trust point keys A and B. Assume that B has been
|
||||
compromised. An attacker could generate and add a new trust anchor
|
||||
key - C (by adding C to the DNSKEY RRSet and signing it with B), and
|
||||
then invalidate the compromised key. This would result in both the
|
||||
attacker and owner being able to sign data in the zone and have it
|
||||
accepted as valid by resolvers.
|
||||
|
||||
To mitigate but not completely solve this problem, we add a hold-down
|
||||
time to the addition of the trust anchor. When the resolver sees a
|
||||
new SEP key in a validated trust point DNSKEY RRSet, the resolver
|
||||
starts an acceptance timer, and remembers all the keys that validated
|
||||
the RRSet. If the resolver ever sees the DNSKEY RRSet without the
|
||||
new key but validly signed, it stops the acceptance process for that
|
||||
key and resets the acceptance timer. If all of the keys which were
|
||||
originally used to validate this key are revoked prior to the timer
|
||||
expiring, the resolver stops the acceptance process and resets the
|
||||
timer.
|
||||
|
||||
Once the timer expires, the new key will be added as a trust anchor
|
||||
the next time the validated RRSet with the new key is seen at the
|
||||
resolver. The resolver MUST NOT treat the new key as a trust anchor
|
||||
until the hold down time expires AND it has retrieved and validated a
|
||||
DNSKEY RRSet after the hold down time which contains the new key.
|
||||
|
||||
N.B.: Once the resolver has accepted a key as a trust anchor, the key
|
||||
MUST be considered a valid trust anchor by that resolver until
|
||||
explictly revoked as described above.
|
||||
|
||||
In the given example, the zone owner can recover from a compromise by
|
||||
revoking B and adding a new key D and signing the DNSKEY RRSet with
|
||||
both A and B.
|
||||
|
||||
The reason this does not completely solve the problem has to do with
|
||||
the distributed nature of DNS. The resolver only knows what it sees.
|
||||
A determined attacker who holds one compromised key could keep a
|
||||
single resolver from realizing that key had been compromised by
|
||||
intercepting 'real' data from the originating zone and substituting
|
||||
their own (e.g. using the example, signed only by B). This is no
|
||||
worse than the current situation assuming a compromised key.
|
||||
|
||||
2.3. Active Refresh
|
||||
|
||||
A resolver which has been configured for automatic update of keys
|
||||
from a particular trust point MUST query that trust point (e.g. do a
|
||||
lookup for the DNSKEY RRSet and related RRSIG records) no less often
|
||||
than the lesser of 15 days or half the original TTL for the DNSKEY
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 5]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
RRSet or half the RRSIG expiration interval and no more often than
|
||||
once per hour. The expiration interval is the amount of time from
|
||||
when the RRSIG was last retrieved until the expiration time in the
|
||||
RRSIG.
|
||||
|
||||
If the query fails, the resolver MUST repeat the query until
|
||||
satisfied no more often than once an hour and no less often than the
|
||||
lesser of 1 day or 10% of the original TTL or 10% of the original
|
||||
expiration interval. I.e.: retryTime = MAX (1 hour, MIN (1 day, .1 *
|
||||
origTTL, .1 * expireInterval)).
|
||||
|
||||
2.4. Resolver Parameters
|
||||
|
||||
2.4.1. Add Hold-Down Time
|
||||
|
||||
The add hold-down time is 30 days or the expiration time of the
|
||||
original TTL of the first trust point DNSKEY RRSet which contained
|
||||
the new key, whichever is greater. This ensures that at least two
|
||||
validated DNSKEY RRSets which contain the new key MUST be seen by the
|
||||
resolver prior to the key's acceptance.
|
||||
|
||||
2.4.2. Remove Hold-Down Time
|
||||
|
||||
The remove hold-down time is 30 days. This parameter is solely a key
|
||||
management database bookeeping parameter. Failure to remove
|
||||
information about the state of defunct keys from the database will
|
||||
not adversely impact the security of this protocol, but may end up
|
||||
with a database cluttered with obsolete key information.
|
||||
|
||||
2.4.3. Minimum Trust Anchors per Trust Point
|
||||
|
||||
A compliant resolver MUST be able to manage at least five SEP keys
|
||||
per trust point.
|
||||
|
||||
|
||||
3. Changes to DNSKEY RDATA Wire Format
|
||||
|
||||
Bit n [msj2]of the DNSKEY Flags field is designated as the 'REVOKE'
|
||||
flag. If this bit is set to '1', AND the resolver sees an
|
||||
RRSIG(DNSKEY) signed by the associated key, then the resolver MUST
|
||||
consider this key permanently invalid for all purposes except for
|
||||
validating the revocation.
|
||||
|
||||
|
||||
4. State Table
|
||||
|
||||
The most important thing to understand is the resolver's view of any
|
||||
key at a trust point. The following state table describes that view
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 6]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
at various points in the key's lifetime. The table is a normative
|
||||
part of this specification. The initial state of the key is 'Start'.
|
||||
The resolver's view of the state of the key changes as various events
|
||||
occur.
|
||||
|
||||
This is the state of a trust point key as seen from the resolver.
|
||||
The column on the left indicates the current state. The header at
|
||||
the top shows the next state. The intersection of the two shows the
|
||||
event that will cause the state to transition from the current state
|
||||
to the next.
|
||||
|
||||
|
||||
NEXT STATE
|
||||
--------------------------------------------------
|
||||
FROM |Start |AddPend |Valid |Missing|Revoked|Removed|
|
||||
----------------------------------------------------------
|
||||
Start | |NewKey | | | | |
|
||||
----------------------------------------------------------
|
||||
AddPend |KeyRem | |AddTime| | |
|
||||
----------------------------------------------------------
|
||||
Valid | | | |KeyRem |Revbit | |
|
||||
----------------------------------------------------------
|
||||
Missing | | |KeyPres| |Revbit | |
|
||||
----------------------------------------------------------
|
||||
Revoked | | | | | |RemTime|
|
||||
----------------------------------------------------------
|
||||
Removed | | | | | | |
|
||||
----------------------------------------------------------
|
||||
|
||||
|
||||
State Table
|
||||
|
||||
4.1. Events
|
||||
NewKey The resolver sees a valid DNSKEY RRSet with a new SEP key.
|
||||
That key will become a new trust anchor for the named trust point
|
||||
after it's been present in the RRSet for at least 'add time'.
|
||||
KeyPres The key has returned to the valid DNSKEY RRSet.
|
||||
KeyRem The resolver sees a valid DNSKEY RRSet that does not contain
|
||||
this key.
|
||||
AddTime The key has been in every valid DNSKEY RRSet seen for at
|
||||
least the 'add time'.
|
||||
RemTime A revoked key has been missing from the trust point DNSKEY
|
||||
RRSet for sufficient time to be removed from the trust set.
|
||||
RevBit The key has appeared in the trust anchor DNSKEY RRSet with
|
||||
its "REVOKED" bit set, and there is an RRSig over the DNSKEY RRSet
|
||||
signed by this key.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 7]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
4.2. States
|
||||
Start The key doesn't yet exist as a trust anchor at the resolver.
|
||||
It may or may not exist at the zone server, but either hasn't yet
|
||||
been seen at the resolver or was seen but was absent from the last
|
||||
DNSKEY RRSet (e.g. KeyRem event).
|
||||
AddPend The key has been seen at the resolver, has its 'SEP' bit
|
||||
set, and has been included in a validated DNSKEY RRSet. There is
|
||||
a hold-down time for the key before it can be used as a trust
|
||||
anchor.
|
||||
Valid The key has been seen at the resolver and has been included in
|
||||
all validated DNSKEY RRSets from the time it was first seen up
|
||||
through the hold-down time. It is now valid for verifying RRSets
|
||||
that arrive after the hold down time. Clarification: The DNSKEY
|
||||
RRSet does not need to be continuously present at the resolver
|
||||
(e.g. its TTL might expire). If the RRSet is seen, and is
|
||||
validated (i.e. verifies against an existing trust anchor), this
|
||||
key MUST be in the RRSet otherwise a 'KeyRem' event is triggered.
|
||||
Missing This is an abnormal state. The key remains as a valid trust
|
||||
point key, but was not seen at the resolver in the last validated
|
||||
DNSKEY RRSet. This is an abnormal state because the zone operator
|
||||
should be using the REVOKE bit prior to removal.
|
||||
Revoked This is the state a key moves to once the resolver sees an
|
||||
RRSIG(DNSKEY) signed by this key where that DNSKEY RRSet contains
|
||||
this key with its REVOKE bit set to '1'. Once in this state, this
|
||||
key MUST permanently be considered invalid as a trust anchor.
|
||||
Removed After a fairly long hold-down time, information about this
|
||||
key may be purged from the resolver. A key in the removed state
|
||||
MUST NOT be considered a valid trust anchor. (Note: this state is
|
||||
more or less equivalent to the "Start" state, except that it's bad
|
||||
practice to re-introduce previously used keys - think of this as
|
||||
the holding state for all the old keys for which the resolver no
|
||||
longer needs to track state.)
|
||||
|
||||
|
||||
5. Trust Point Deletion
|
||||
|
||||
A trust point which has all of its trust anchors revoked is
|
||||
considered deleted and is treated as if the trust point was never
|
||||
configured. If there are no superior configured trust points, data
|
||||
at and below the deleted trust point are considered insecure by the
|
||||
resolver. If there ARE superior configured trust points, data at and
|
||||
below the deleted trust point are evaluated with respect to the
|
||||
superior trust point(s).
|
||||
|
||||
Alternately, a trust point which is subordinate to another configured
|
||||
trust point MAY be deleted by a resolver after 180 days where such
|
||||
subordinate trust point validly chains to a superior trust point.
|
||||
The decision to delete the subordinate trust anchor is a local
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 8]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
configuration decision. Once the subordinate trust point is deleted,
|
||||
validation of the subordinate zone is dependent on validating the
|
||||
chain of trust to the superior trust point.
|
||||
|
||||
|
||||
6. Scenarios - Informative
|
||||
|
||||
The suggested model for operation is to have one active key and one
|
||||
stand-by key at each trust point. The active key will be used to
|
||||
sign the DNSKEY RRSet. The stand-by key will not normally sign this
|
||||
RRSet, but the resolver will accept it as a trust anchor if/when it
|
||||
sees the signature on the trust point DNSKEY RRSet.
|
||||
|
||||
Since the stand-by key is not in active signing use, the associated
|
||||
private key may (and should) be provided with additional protections
|
||||
not normally available to a key that must be used frequently. E.g.
|
||||
locked in a safe, split among many parties, etc. Notionally, the
|
||||
stand-by key should be less subject to compromise than an active key,
|
||||
but that will be dependent on operational concerns not addressed
|
||||
here.
|
||||
|
||||
6.1. Adding a Trust Anchor
|
||||
|
||||
Assume an existing trust anchor key 'A'.
|
||||
1. Generate a new key pair.
|
||||
2. Create a DNSKEY record from the key pair and set the SEP and Zone
|
||||
Key bits.
|
||||
3. Add the DNSKEY to the RRSet.
|
||||
4. Sign the DNSKEY RRSet ONLY with the existing trust anchor key -
|
||||
'A'.
|
||||
5. Wait a while (i.e. for various resolvers timers to go off and for
|
||||
them to retrieve the new DNSKEY RRSet and signatures).
|
||||
6. The new trust anchor will be populated at the resolvers on the
|
||||
schedule described by the state table and update algorithm - see
|
||||
Section 2 above
|
||||
|
||||
6.2. Deleting a Trust Anchor
|
||||
|
||||
Assume existing trust anchors 'A' and 'B' and that you want to revoke
|
||||
and delete 'A'.
|
||||
1. Set the revocation bit on key 'A'.
|
||||
2. Sign the DNSKEY RRSet with both 'A' and 'B'.
|
||||
'A' is now revoked. The operator should include the revoked 'A' in
|
||||
the RRSet for at least the remove hold-down time, but then may remove
|
||||
it from the DNSKEY RRSet.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 9]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
6.3. Key Roll-Over
|
||||
|
||||
Assume existing keys A and B. 'A' is actively in use (i.e. has been
|
||||
signing the DNSKEY RRSet.) 'B' was the stand-by key. (i.e. has been
|
||||
in the DNSKEY RRSet and is a valid trust anchor, but wasn't being
|
||||
used to sign the RRSet.)
|
||||
1. Generate a new key pair 'C'.
|
||||
2. Add 'C' to the DNSKEY RRSet.
|
||||
3. Set the revocation bit on key 'A'.
|
||||
4. Sign the RRSet with 'A' and 'B'.
|
||||
'A' is now revoked, 'B' is now the active key, and 'C' will be the
|
||||
stand-by key once the hold-down expires. The operator should include
|
||||
the revoked 'A' in the RRSet for at least the remove hold-down time,
|
||||
but may then remove it from the DNSKEY RRSet.
|
||||
|
||||
6.4. Active Key Compromised
|
||||
|
||||
This is the same as the mechanism for Key Roll-Over (Section 6.3)
|
||||
above assuming 'A' is the active key.
|
||||
|
||||
6.5. Stand-by Key Compromised
|
||||
|
||||
Using the same assumptions and naming conventions as Key Roll-Over
|
||||
(Section 6.3) above:
|
||||
1. Generate a new key pair 'C'.
|
||||
2. Add 'C' to the DNSKEY RRSet.
|
||||
3. Set the revocation bit on key 'B'.
|
||||
4. Sign the RRSet with 'A' and 'B'.
|
||||
'B' is now revoked, 'A' remains the active key, and 'C' will be the
|
||||
stand-by key once the hold-down expires. 'B' should continue to be
|
||||
included in the RRSet for the remove hold-down time.
|
||||
|
||||
6.6. Trust Point Deletion
|
||||
|
||||
To delete a trust point which is subordinate to another configured
|
||||
trust point (e.g. example.com to .com) requires some juggling of the
|
||||
data. The specific process is:
|
||||
1. Generate a new DNSKEY and DS record and provide the DS record to
|
||||
the parent along with DS records for the old keys
|
||||
2. Once the parent has published the DSs, add the new DNSKEY to the
|
||||
RRSet and revoke ALL of the old keys at the same time while
|
||||
signing the DNSKEY RRSet with all of the old and new keys.
|
||||
3. After 30 days stop publishing the old, revoked keys and remove
|
||||
any corresponding DS records in the parent.
|
||||
Revoking the old trust point keys at the same time as adding new keys
|
||||
that chain to a superior trust prevents the resolver from adding the
|
||||
new keys as trust anchors. Adding DS records for the old keys avoids
|
||||
a race condition where either the subordinate zone becomes unsecure
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 10]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
(because the trust point was deleted) or becomes bogus (because it
|
||||
didn't chain to the superior zone).
|
||||
|
||||
|
||||
7. IANA Considerations
|
||||
|
||||
The IANA will need to assign a bit in the DNSKEY flags field (see
|
||||
section 4.3 of [RFC3755]) for the REVOKE bit. There are no other
|
||||
IANA actions required.
|
||||
|
||||
|
||||
8. Security Considerations
|
||||
|
||||
In addition to the following sections, see also Theory of Operation
|
||||
above and especially Section 2.2 for related discussions.
|
||||
|
||||
8.1. Key Ownership vs Acceptance Policy
|
||||
|
||||
The reader should note that, while the zone owner is responsible for
|
||||
creating and distributing keys, it's wholly the decision of the
|
||||
resolver owner as to whether to accept such keys for the
|
||||
authentication of the zone information. This implies the decision to
|
||||
update trust anchor keys based on trust for a current trust anchor
|
||||
key is also the resolver owner's decision.
|
||||
|
||||
The resolver owner (and resolver implementers) MAY choose to permit
|
||||
or prevent key status updates based on this mechanism for specific
|
||||
trust points. If they choose to prevent the automated updates, they
|
||||
will need to establish a mechanism for manual or other out-of-band
|
||||
updates outside the scope of this document.
|
||||
|
||||
8.2. Multiple Key Compromise
|
||||
|
||||
This scheme permits recovery as long as at least one valid trust
|
||||
anchor key remains uncompromised. E.g. if there are three keys, you
|
||||
can recover if two of them are compromised. The zone owner should
|
||||
determine their own level of comfort with respect to the number of
|
||||
active valid trust anchors in a zone and should be prepared to
|
||||
implement recovery procedures once they detect a compromise. A
|
||||
manual or other out-of-band update of all resolvers will be required
|
||||
if all trust anchor keys at a trust point are compromised.
|
||||
|
||||
8.3. Dynamic Updates
|
||||
|
||||
Allowing a resolver to update its trust anchor set based on in-band
|
||||
key information is potentially less secure than a manual process.
|
||||
However, given the nature of the DNS, the number of resolvers that
|
||||
would require update if a trust anchor key were compromised, and the
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 11]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
lack of a standard management framework for DNS, this approach is no
|
||||
worse than the existing situation.
|
||||
|
||||
|
||||
9. Normative References
|
||||
|
||||
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
|
||||
Requirement Levels", BCP 14, RFC 2119, March 1997.
|
||||
|
||||
[RFC3755] Weiler, S., "Legacy Resolver Compatibility for Delegation
|
||||
Signer (DS)", RFC 3755, May 2004.
|
||||
|
||||
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "DNS Security Introduction and Requirements",
|
||||
RFC 4033, March 2005.
|
||||
|
||||
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Resource Records for the DNS Security Extensions",
|
||||
RFC 4034, March 2005.
|
||||
|
||||
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
|
||||
Rose, "Protocol Modifications for the DNS Security
|
||||
Extensions", RFC 4035, March 2005.
|
||||
|
||||
Editorial Comments
|
||||
|
||||
[msj2] msj: To be assigned.
|
||||
|
||||
|
||||
Author's Address
|
||||
|
||||
Michael StJohns
|
||||
Nominum, Inc.
|
||||
2385 Bay Road
|
||||
Redwood City, CA 94063
|
||||
USA
|
||||
|
||||
Phone: +1-301-528-4729
|
||||
Email: Mike.StJohns@nominum.com
|
||||
URI: www.nominum.com
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 12]
|
||||
|
||||
Internet-Draft trustanchor-update November 2006
|
||||
|
||||
|
||||
Full Copyright Statement
|
||||
|
||||
Copyright (C) The Internet Society (2006).
|
||||
|
||||
This document is subject to the rights, licenses and restrictions
|
||||
contained in BCP 78, and except as set forth therein, the authors
|
||||
retain all their rights.
|
||||
|
||||
This document and the information contained herein are provided on an
|
||||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
|
||||
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
|
||||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
|
||||
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
|
||||
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
|
||||
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
||||
|
||||
|
||||
Intellectual Property
|
||||
|
||||
The IETF takes no position regarding the validity or scope of any
|
||||
Intellectual Property Rights or other rights that might be claimed to
|
||||
pertain to the implementation or use of the technology described in
|
||||
this document or the extent to which any license under such rights
|
||||
might or might not be available; nor does it represent that it has
|
||||
made any independent effort to identify any such rights. Information
|
||||
on the procedures with respect to rights in RFC documents can be
|
||||
found in BCP 78 and BCP 79.
|
||||
|
||||
Copies of IPR disclosures made to the IETF Secretariat and any
|
||||
assurances of licenses to be made available, or the result of an
|
||||
attempt made to obtain a general license or permission for the use of
|
||||
such proprietary rights by implementers or users of this
|
||||
specification can be obtained from the IETF on-line IPR repository at
|
||||
http://www.ietf.org/ipr.
|
||||
|
||||
The IETF invites any interested party to bring to its attention any
|
||||
copyrights, patents or patent applications, or other proprietary
|
||||
rights that may cover technology that may be required to implement
|
||||
this standard. Please address the information to the IETF at
|
||||
ietf-ipr@ietf.org.
|
||||
|
||||
|
||||
Acknowledgment
|
||||
|
||||
Funding for the RFC Editor function is provided by the IETF
|
||||
Administrative Support Activity (IASA).
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
StJohns Expires June 2, 2007 [Page 13]
|
||||
|
||||
|
||||
@@ -1,640 +0,0 @@
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
DNSOP Working Group Paul Vixie, ISC
|
||||
INTERNET-DRAFT Akira Kato, WIDE
|
||||
<draft-ietf-dnsop-respsize-06.txt> August 2006
|
||||
|
||||
DNS Referral Response Size Issues
|
||||
|
||||
Status of this Memo
|
||||
By submitting this Internet-Draft, each author represents that any
|
||||
applicable patent or other IPR claims of which he or she is aware
|
||||
have been or will be disclosed, and any of which he or she becomes
|
||||
aware will be disclosed, in accordance with Section 6 of BCP 79.
|
||||
|
||||
Internet-Drafts are working documents of the Internet Engineering
|
||||
Task Force (IETF), its areas, and its working groups. Note that
|
||||
other groups may also distribute working documents as Internet-
|
||||
Drafts.
|
||||
|
||||
Internet-Drafts are draft documents valid for a maximum of six months
|
||||
and may be updated, replaced, or obsoleted by other documents at any
|
||||
time. It is inappropriate to use Internet-Drafts as reference
|
||||
material or to cite them other than as "work in progress."
|
||||
|
||||
The list of current Internet-Drafts can be accessed at
|
||||
http://www.ietf.org/ietf/1id-abstracts.txt
|
||||
|
||||
The list of Internet-Draft Shadow Directories can be accessed at
|
||||
http://www.ietf.org/shadow.html.
|
||||
|
||||
Copyright Notice
|
||||
|
||||
Copyright (C) The Internet Society (2006). All Rights Reserved.
|
||||
|
||||
|
||||
|
||||
|
||||
Abstract
|
||||
|
||||
With a mandated default minimum maximum message size of 512 octets,
|
||||
the DNS protocol presents some special problems for zones wishing to
|
||||
expose a moderate or high number of authority servers (NS RRs). This
|
||||
document explains the operational issues caused by, or related to
|
||||
this response size limit, and suggests ways to optimize the use of
|
||||
this limited space. Guidance is offered to DNS server implementors
|
||||
and to DNS zone operators.
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 1]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
1 - Introduction and Overview
|
||||
|
||||
1.1. The DNS standard (see [RFC1035 4.2.1]) limits message size to 512
|
||||
octets. Even though this limitation was due to the required minimum IP
|
||||
reassembly limit for IPv4, it became a hard DNS protocol limit and is
|
||||
not implicitly relaxed by changes in transport, for example to IPv6.
|
||||
|
||||
1.2. The EDNS0 protocol extension (see [RFC2671 2.3, 4.5]) permits
|
||||
larger responses by mutual agreement of the requester and responder.
|
||||
The 512 octet message size limit will remain in practical effect until
|
||||
there is widespread deployment of EDNS0 in DNS resolvers on the
|
||||
Internet.
|
||||
|
||||
1.3. Since DNS responses include a copy of the request, the space
|
||||
available for response data is somewhat less than the full 512 octets.
|
||||
Negative responses are quite small, but for positive and delegation
|
||||
responses, every octet must be carefully and sparingly allocated. This
|
||||
document specifically addresses delegation response sizes.
|
||||
|
||||
2 - Delegation Details
|
||||
|
||||
2.1. RELEVANT PROTOCOL ELEMENTS
|
||||
|
||||
2.1.1. A delegation response will include the following elements:
|
||||
|
||||
Header Section: fixed length (12 octets)
|
||||
Question Section: original query (name, class, type)
|
||||
Answer Section: empty, or a CNAME/DNAME chain
|
||||
Authority Section: NS RRset (nameserver names)
|
||||
Additional Section: A and AAAA RRsets (nameserver addresses)
|
||||
|
||||
2.1.2. If the total response size exceeds 512 octets, and if the data
|
||||
that does not fit was "required", then the TC bit will be set
|
||||
(indicating truncation). This will usually cause the requester to retry
|
||||
using TCP, depending on what information was desired and what
|
||||
information was omitted. For example, truncation in the authority
|
||||
section is of no interest to a stub resolver who only plans to consume
|
||||
the answer section. If a retry using TCP is needed, the total cost of
|
||||
the transaction is much higher. See [RFC1123 6.1.3.2] for details on
|
||||
the requirement that UDP be attempted before falling back to TCP.
|
||||
|
||||
2.1.3. RRsets are never sent partially unless TC bit set to indicate
|
||||
truncation. When TC bit is set, the final apparent RRset in the final
|
||||
non-empty section must be considered "possibly damaged" (see [RFC1035
|
||||
6.2], [RFC2181 9]).
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 2]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
2.1.4. With or without truncation, the glue present in the additional
|
||||
data section should be considered "possibly incomplete", and requesters
|
||||
should be prepared to re-query for any damaged or missing RRsets. Note
|
||||
that truncation of the additional data section might not be signalled
|
||||
via the TC bit since additional data is often optional (see discussion
|
||||
in [RFC4472 B]).
|
||||
|
||||
2.1.5. DNS label compression allows a domain name to be instantiated
|
||||
only once per DNS message, and then referenced with a two-octet
|
||||
"pointer" from other locations in that same DNS message (see [RFC1035
|
||||
4.1.4]). If all nameserver names in a message share a common parent
|
||||
(for example, all ending in ".ROOT-SERVERS.NET"), then more space will
|
||||
be available for incompressable data (such as nameserver addresses).
|
||||
|
||||
2.1.6. The query name can be as long as 255 octets of network data. In
|
||||
this worst case scenario, the question section will be 259 octets in
|
||||
size, which would leave only 240 octets for the authority and additional
|
||||
sections (after deducting 12 octets for the fixed length header.)
|
||||
|
||||
2.2. ADVICE TO ZONE OWNERS
|
||||
|
||||
2.2.1. Average and maximum question section sizes can be predicted by
|
||||
the zone owner, since they will know what names actually exist, and can
|
||||
measure which ones are queried for most often. Note that if the zone
|
||||
contains any wildcards, it is possible for maximum length queries to
|
||||
require positive responses, but that it is reasonable to expect
|
||||
truncation and TCP retry in that case. For cost and performance
|
||||
reasons, the majority of requests should be satisfied without truncation
|
||||
or TCP retry.
|
||||
|
||||
2.2.2. Some queries to non-existing names can be large, but this is not
|
||||
a problem because negative responses need not contain any answer,
|
||||
authority or additional records. See [RFC2308 2.1] for more information
|
||||
about the format of negative responses.
|
||||
|
||||
2.2.3. The minimum useful number of name servers is two, for redundancy
|
||||
(see [RFC1034 4.1]). A zone's name servers should be reachable by all
|
||||
IP transport protocols (e.g., IPv4 and IPv6) in common use.
|
||||
|
||||
2.2.4. The best case is no truncation at all. This is because many
|
||||
requesters will retry using TCP immediately, or will automatically re-
|
||||
query for RRsets that are possibly truncated, without considering
|
||||
whether the omitted data was actually necessary.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 3]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
2.3. ADVICE TO SERVER IMPLEMENTORS
|
||||
|
||||
2.3.1. In case of multi-homed name servers, it is advantageous to
|
||||
include an address record from each of several name servers before
|
||||
including several address records for any one name server. If address
|
||||
records for more than one transport (for example, A and AAAA) are
|
||||
available, then it is advantageous to include records of both types
|
||||
early on, before the message is full.
|
||||
|
||||
2.3.2. Each added NS RR for a zone will add 12 fixed octets (name, type,
|
||||
class, ttl, and rdlen) plus 2 to 255 variable octets (for the NSDNAME).
|
||||
Each A RR will require 16 octets, and each AAAA RR will require 28
|
||||
octets.
|
||||
|
||||
2.3.3. While DNS distinguishes between necessary and optional resource
|
||||
records, this distinction is according to protocol elements necessary to
|
||||
signify facts, and takes no official notice of protocol content
|
||||
necessary to ensure correct operation. For example, a nameserver name
|
||||
that is in or below the zone cut being described by a delegation is
|
||||
"necessary content," since there is no way to reach that zone unless the
|
||||
parent zone's delegation includes "glue records" describing that name
|
||||
server's addresses.
|
||||
|
||||
2.3.4. It is also necessary to distinguish between "explicit truncation"
|
||||
where a message could not contain enough records to convey its intended
|
||||
meaning, and so the TC bit has been set, and "silent truncation", where
|
||||
the message was not large enough to contain some records which were "not
|
||||
required", and so the TC bit was not set.
|
||||
|
||||
2.3.5. A delegation response should prioritize glue records as follows.
|
||||
|
||||
first
|
||||
All glue RRsets for one name server whose name is in or below the
|
||||
zone being delegated, or which has multiple address RRsets (currently
|
||||
A and AAAA), or preferably both;
|
||||
|
||||
second
|
||||
Alternate between adding all glue RRsets for any name servers whose
|
||||
names are in or below the zone being delegated, and all glue RRsets
|
||||
for any name servers who have multiple address RRsets (currently A
|
||||
and AAAA);
|
||||
|
||||
thence
|
||||
All other glue RRsets, in any order.
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 4]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
Whenever there are multiple candidates for a position in this priority
|
||||
scheme, one should be chosen on a round-robin or fully random basis.
|
||||
|
||||
The goal of this priority scheme is to offer "necessary" glue first,
|
||||
avoiding silent truncation for this glue if possible.
|
||||
|
||||
2.3.6. If any "necessary content" is silently truncated, then it is
|
||||
advisable that the TC bit be set in order to force a TCP retry, rather
|
||||
than have the zone be unreachable. Note that a parent server's proper
|
||||
response to a query for in-child glue or below-child glue is a referral
|
||||
rather than an answer, and that this referral MUST be able to contain
|
||||
the in-child or below-child glue, and that in outlying cases, only EDNS
|
||||
or TCP will be large enough to contain that data.
|
||||
|
||||
3 - Analysis
|
||||
|
||||
3.1. An instrumented protocol trace of a best case delegation response
|
||||
follows. Note that 13 servers are named, and 13 addresses are given.
|
||||
This query was artificially designed to exactly reach the 512 octet
|
||||
limit.
|
||||
|
||||
;; flags: qr rd; QUERY: 1, ANS: 0, AUTH: 13, ADDIT: 13
|
||||
;; QUERY SECTION:
|
||||
;; [23456789.123456789.123456789.\
|
||||
123456789.123456789.123456789.com A IN] ;; @80
|
||||
|
||||
;; AUTHORITY SECTION:
|
||||
com. 86400 NS E.GTLD-SERVERS.NET. ;; @112
|
||||
com. 86400 NS F.GTLD-SERVERS.NET. ;; @128
|
||||
com. 86400 NS G.GTLD-SERVERS.NET. ;; @144
|
||||
com. 86400 NS H.GTLD-SERVERS.NET. ;; @160
|
||||
com. 86400 NS I.GTLD-SERVERS.NET. ;; @176
|
||||
com. 86400 NS J.GTLD-SERVERS.NET. ;; @192
|
||||
com. 86400 NS K.GTLD-SERVERS.NET. ;; @208
|
||||
com. 86400 NS L.GTLD-SERVERS.NET. ;; @224
|
||||
com. 86400 NS M.GTLD-SERVERS.NET. ;; @240
|
||||
com. 86400 NS A.GTLD-SERVERS.NET. ;; @256
|
||||
com. 86400 NS B.GTLD-SERVERS.NET. ;; @272
|
||||
com. 86400 NS C.GTLD-SERVERS.NET. ;; @288
|
||||
com. 86400 NS D.GTLD-SERVERS.NET. ;; @304
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 5]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
;; ADDITIONAL SECTION:
|
||||
A.GTLD-SERVERS.NET. 86400 A 192.5.6.30 ;; @320
|
||||
B.GTLD-SERVERS.NET. 86400 A 192.33.14.30 ;; @336
|
||||
C.GTLD-SERVERS.NET. 86400 A 192.26.92.30 ;; @352
|
||||
D.GTLD-SERVERS.NET. 86400 A 192.31.80.30 ;; @368
|
||||
E.GTLD-SERVERS.NET. 86400 A 192.12.94.30 ;; @384
|
||||
F.GTLD-SERVERS.NET. 86400 A 192.35.51.30 ;; @400
|
||||
G.GTLD-SERVERS.NET. 86400 A 192.42.93.30 ;; @416
|
||||
H.GTLD-SERVERS.NET. 86400 A 192.54.112.30 ;; @432
|
||||
I.GTLD-SERVERS.NET. 86400 A 192.43.172.30 ;; @448
|
||||
J.GTLD-SERVERS.NET. 86400 A 192.48.79.30 ;; @464
|
||||
K.GTLD-SERVERS.NET. 86400 A 192.52.178.30 ;; @480
|
||||
L.GTLD-SERVERS.NET. 86400 A 192.41.162.30 ;; @496
|
||||
M.GTLD-SERVERS.NET. 86400 A 192.55.83.30 ;; @512
|
||||
|
||||
;; MSG SIZE sent: 80 rcvd: 512
|
||||
|
||||
3.2. For longer query names, the number of address records supplied will
|
||||
be lower. Furthermore, it is only by using a common parent name (which
|
||||
is GTLD-SERVERS.NET in this example) that all 13 addresses are able to
|
||||
fit, due to the use of DNS compression pointers in the last 12
|
||||
occurances of the parent domain name. The following output from a
|
||||
response simulator demonstrates these properties.
|
||||
|
||||
% perl respsize.pl a.dns.br b.dns.br c.dns.br d.dns.br
|
||||
a.dns.br requires 10 bytes
|
||||
b.dns.br requires 4 bytes
|
||||
c.dns.br requires 4 bytes
|
||||
d.dns.br requires 4 bytes
|
||||
# of NS: 4
|
||||
For maximum size query (255 byte):
|
||||
only A is considered: # of A is 4 (green)
|
||||
A and AAAA are considered: # of A+AAAA is 3 (yellow)
|
||||
preferred-glue A is assumed: # of A is 4, # of AAAA is 3 (yellow)
|
||||
For average size query (64 byte):
|
||||
only A is considered: # of A is 4 (green)
|
||||
A and AAAA are considered: # of A+AAAA is 4 (green)
|
||||
preferred-glue A is assumed: # of A is 4, # of AAAA is 4 (green)
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 6]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
% perl respsize.pl ns-ext.isc.org ns.psg.com ns.ripe.net ns.eu.int
|
||||
ns-ext.isc.org requires 16 bytes
|
||||
ns.psg.com requires 12 bytes
|
||||
ns.ripe.net requires 13 bytes
|
||||
ns.eu.int requires 11 bytes
|
||||
# of NS: 4
|
||||
For maximum size query (255 byte):
|
||||
only A is considered: # of A is 4 (green)
|
||||
A and AAAA are considered: # of A+AAAA is 3 (yellow)
|
||||
preferred-glue A is assumed: # of A is 4, # of AAAA is 2 (yellow)
|
||||
For average size query (64 byte):
|
||||
only A is considered: # of A is 4 (green)
|
||||
A and AAAA are considered: # of A+AAAA is 4 (green)
|
||||
preferred-glue A is assumed: # of A is 4, # of AAAA is 4 (green)
|
||||
|
||||
(Note: The response simulator program is shown in Section 5.)
|
||||
|
||||
Here we use the term "green" if all address records could fit, or
|
||||
"yellow" if two or more could fit, or "orange" if only one could fit, or
|
||||
"red" if no address record could fit. It's clear that without a common
|
||||
parent for nameserver names, much space would be lost. For these
|
||||
examples we use an average/common name size of 15 octets, befitting our
|
||||
assumption of GTLD-SERVERS.NET as our common parent name.
|
||||
|
||||
We're assuming a medium query name size of 64 since that is the typical
|
||||
size seen in trace data at the time of this writing. If
|
||||
Internationalized Domain Name (IDN) or any other technology which
|
||||
results in larger query names be deployed significantly in advance of
|
||||
EDNS, then new measurements and new estimates will have to be made.
|
||||
|
||||
4 - Conclusions
|
||||
|
||||
4.1. The current practice of giving all nameserver names a common parent
|
||||
(such as GTLD-SERVERS.NET or ROOT-SERVERS.NET) saves space in DNS
|
||||
responses and allows for more nameservers to be enumerated than would
|
||||
otherwise be possible, since the common parent domain name only appears
|
||||
once in a DNS message and is referred to via "compression pointers"
|
||||
thereafter.
|
||||
|
||||
4.2. If all nameserver names for a zone share a common parent, then it
|
||||
is operationally advisable to make all servers for the zone thus served
|
||||
also be authoritative for the zone of that common parent. For example,
|
||||
the root name servers (?.ROOT-SERVERS.NET) can answer authoritatively
|
||||
for the ROOT-SERVERS.NET. This is to ensure that the zone's servers
|
||||
always have the zone's nameservers' glue available when delegating, and
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 7]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
will be able to respond with answers rather than referrals if a
|
||||
requester who wants that glue comes back asking for it. In this case
|
||||
the name server will likely be a "stealth server" -- authoritative but
|
||||
unadvertised in the glue zone's NS RRset. See [RFC1996 2] for more
|
||||
information about stealth servers.
|
||||
|
||||
4.3. Thirteen (13) is the effective maximum number of nameserver names
|
||||
usable traditional (non-extended) DNS, assuming a common parent domain
|
||||
name, and given that implicit referral response truncation is
|
||||
undesirable in the average case.
|
||||
|
||||
4.4. Multi-homing of name servers within a protocol family is
|
||||
inadvisable since the necessary glue RRsets (A or AAAA) are atomically
|
||||
indivisible, and will be larger than a single resource record. Larger
|
||||
RRsets are more likely to lead to or encounter truncation.
|
||||
|
||||
4.5. Multi-homing of name servers across protocol families is less
|
||||
likely to lead to or encounter truncation, partly because multiprotocol
|
||||
clients are more likely to speak EDNS which can use a larger response
|
||||
size limit, and partly because the resource records (A and AAAA) are in
|
||||
different RRsets and are therefore divisible from each other.
|
||||
|
||||
4.6. Name server names which are at or below the zone they serve are
|
||||
more sensitive to referral response truncation, and glue records for
|
||||
them should be considered "less optional" than other glue records, in
|
||||
the assembly of referral responses.
|
||||
|
||||
4.7. If a zone is served by thirteen (13) name servers having a common
|
||||
parent name (such as ?.ROOT-SERVERS.NET) and each such name server has a
|
||||
single address record in some protocol family (e.g., an A RR), then all
|
||||
thirteen name servers or any subset thereof could multi-home in a second
|
||||
protocol family by adding a second address record (e.g., an AAAA RR)
|
||||
without reducing the reachability of the zone thus served.
|
||||
|
||||
5 - Source Code
|
||||
|
||||
#!/usr/bin/perl
|
||||
#
|
||||
# SYNOPSIS
|
||||
# repsize.pl [ -z zone ] fqdn_ns1 fqdn_ns2 ...
|
||||
# if all queries are assumed to have a same zone suffix,
|
||||
# such as "jp" in JP TLD servers, specify it in -z option
|
||||
#
|
||||
use strict;
|
||||
use Getopt::Std;
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 8]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
my ($sz_msg) = (512);
|
||||
my ($sz_header, $sz_ptr, $sz_rr_a, $sz_rr_aaaa) = (12, 2, 16, 28);
|
||||
my ($sz_type, $sz_class, $sz_ttl, $sz_rdlen) = (2, 2, 4, 2);
|
||||
my (%namedb, $name, $nssect, %opts, $optz);
|
||||
my $n_ns = 0;
|
||||
|
||||
getopt('z', %opts);
|
||||
if (defined($opts{'z'})) {
|
||||
server_name_len($opts{'z'}); # just register it
|
||||
}
|
||||
|
||||
foreach $name (@ARGV) {
|
||||
my $len;
|
||||
$n_ns++;
|
||||
$len = server_name_len($name);
|
||||
print "$name requires $len bytes\n";
|
||||
$nssect += $sz_ptr + $sz_type + $sz_class + $sz_ttl
|
||||
+ $sz_rdlen + $len;
|
||||
}
|
||||
print "# of NS: $n_ns\n";
|
||||
arsect(255, $nssect, $n_ns, "maximum");
|
||||
arsect(64, $nssect, $n_ns, "average");
|
||||
|
||||
sub server_name_len {
|
||||
my ($name) = @_;
|
||||
my (@labels, $len, $n, $suffix);
|
||||
|
||||
$name =~ tr/A-Z/a-z/;
|
||||
@labels = split(/\./, $name);
|
||||
$len = length(join('.', @labels)) + 2;
|
||||
for ($n = 0; $#labels >= 0; $n++, shift @labels) {
|
||||
$suffix = join('.', @labels);
|
||||
return length($name) - length($suffix) + $sz_ptr
|
||||
if (defined($namedb{$suffix}));
|
||||
$namedb{$suffix} = 1;
|
||||
}
|
||||
return $len;
|
||||
}
|
||||
|
||||
sub arsect {
|
||||
my ($sz_query, $nssect, $n_ns, $cond) = @_;
|
||||
my ($space, $n_a, $n_a_aaaa, $n_p_aaaa, $ansect);
|
||||
$ansect = $sz_query + 1 + $sz_type + $sz_class;
|
||||
$space = $sz_msg - $sz_header - $ansect - $nssect;
|
||||
$n_a = atmost(int($space / $sz_rr_a), $n_ns);
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 9]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
$n_a_aaaa = atmost(int($space
|
||||
/ ($sz_rr_a + $sz_rr_aaaa)), $n_ns);
|
||||
$n_p_aaaa = atmost(int(($space - $sz_rr_a * $n_ns)
|
||||
/ $sz_rr_aaaa), $n_ns);
|
||||
printf "For %s size query (%d byte):\n", $cond, $sz_query;
|
||||
printf " only A is considered: ";
|
||||
printf "# of A is %d (%s)\n", $n_a, &judge($n_a, $n_ns);
|
||||
printf " A and AAAA are considered: ";
|
||||
printf "# of A+AAAA is %d (%s)\n",
|
||||
$n_a_aaaa, &judge($n_a_aaaa, $n_ns);
|
||||
printf " preferred-glue A is assumed: ";
|
||||
printf "# of A is %d, # of AAAA is %d (%s)\n",
|
||||
$n_a, $n_p_aaaa, &judge($n_p_aaaa, $n_ns);
|
||||
}
|
||||
|
||||
sub judge {
|
||||
my ($n, $n_ns) = @_;
|
||||
return "green" if ($n >= $n_ns);
|
||||
return "yellow" if ($n >= 2);
|
||||
return "orange" if ($n == 1);
|
||||
return "red";
|
||||
}
|
||||
|
||||
sub atmost {
|
||||
my ($a, $b) = @_;
|
||||
return 0 if ($a < 0);
|
||||
return $b if ($a > $b);
|
||||
return $a;
|
||||
}
|
||||
|
||||
6 - Security Considerations
|
||||
|
||||
The recommendations contained in this document have no known security
|
||||
implications.
|
||||
|
||||
7 - IANA Considerations
|
||||
|
||||
This document does not call for changes or additions to any IANA
|
||||
registry.
|
||||
|
||||
8 - Acknowledgement
|
||||
|
||||
The authors thank Peter Koch, Rob Austein, Joe Abley, and Mark Andrews
|
||||
for their valuable comments and suggestions.
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 10]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
This work was supported by the US National Science Foundation (research
|
||||
grant SCI-0427144) and DNS-OARC.
|
||||
|
||||
9 - References
|
||||
|
||||
[RFC1034] Mockapetris, P.V., "Domain names - Concepts and Facilities",
|
||||
RFC1034, November 1987.
|
||||
|
||||
[RFC1035] Mockapetris, P.V., "Domain names - Implementation and
|
||||
Specification", RFC1035, November 1987.
|
||||
|
||||
[RFC1123] Braden, R., Ed., "Requirements for Internet Hosts -
|
||||
Application and Support", RFC1123, October 1989.
|
||||
|
||||
[RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone
|
||||
Changes (DNS NOTIFY)", RFC1996, August 1996.
|
||||
|
||||
[RFC2181] Elz, R., Bush, R., "Clarifications to the DNS Specification",
|
||||
RFC2181, July 1997.
|
||||
|
||||
[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)",
|
||||
RFC2308, March 1998.
|
||||
|
||||
[RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC2671,
|
||||
August 1999.
|
||||
|
||||
[RFC4472] Durand, A., Ihren, J., Savola, P., "Operational Consideration
|
||||
and Issues with IPV6 DNS", April 2006.
|
||||
|
||||
10 - Authors' Addresses
|
||||
|
||||
Paul Vixie
|
||||
Internet Systems Consortium, Inc.
|
||||
950 Charter Street
|
||||
Redwood City, CA 94063
|
||||
+1 650 423 1301
|
||||
vixie@isc.org
|
||||
|
||||
Akira Kato
|
||||
University of Tokyo, Information Technology Center
|
||||
2-11-16 Yayoi Bunkyo
|
||||
Tokyo 113-8658, JAPAN
|
||||
+81 3 5841 2750
|
||||
kato@wide.ad.jp
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 11]
|
||||
|
||||
INTERNET-DRAFT August 2006 RESPSIZE
|
||||
|
||||
|
||||
Full Copyright Statement
|
||||
|
||||
Copyright (C) The Internet Society (2006).
|
||||
|
||||
This document is subject to the rights, licenses and restrictions
|
||||
contained in BCP 78, and except as set forth therein, the authors retain
|
||||
all their rights.
|
||||
|
||||
This document and the information contained herein are provided on an
|
||||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR
|
||||
IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
|
||||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
|
||||
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
|
||||
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
|
||||
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
||||
|
||||
Intellectual Property
|
||||
|
||||
The IETF takes no position regarding the validity or scope of any
|
||||
Intellectual Property Rights or other rights that might be claimed to
|
||||
pertain to the implementation or use of the technology described in this
|
||||
document or the extent to which any license under such rights might or
|
||||
might not be available; nor does it represent that it has made any
|
||||
independent effort to identify any such rights. Information on the
|
||||
procedures with respect to rights in RFC documents can be found in BCP
|
||||
78 and BCP 79.
|
||||
|
||||
Copies of IPR disclosures made to the IETF Secretariat and any
|
||||
assurances of licenses to be made available, or the result of an attempt
|
||||
made to obtain a general license or permission for the use of such
|
||||
proprietary rights by implementers or users of this specification can be
|
||||
obtained from the IETF on-line IPR repository at
|
||||
http://www.ietf.org/ipr.
|
||||
|
||||
The IETF invites any interested party to bring to its attention any
|
||||
copyrights, patents or patent applications, or other proprietary rights
|
||||
that may cover technology that may be required to implement this
|
||||
standard. Please address the information to the IETF at
|
||||
ietf-ipr@ietf.org.
|
||||
|
||||
Acknowledgement
|
||||
|
||||
Funding for the RFC Editor function is provided by the IETF
|
||||
Administrative Support Activity (IASA).
|
||||
|
||||
|
||||
|
||||
|
||||
Expires January 2007 [Page 12]
|
||||
|
||||
|
||||
@@ -1,50 +0,0 @@
|
||||
#!/bin/perl
|
||||
#
|
||||
# Copyright (C) 2007 Internet Systems Consortium, Inc. ("ISC")
|
||||
#
|
||||
# Permission to use, copy, modify, and/or distribute this software for any
|
||||
# purpose with or without fee is hereby granted, provided that the above
|
||||
# copyright notice and this permission notice appear in all copies.
|
||||
#
|
||||
# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
|
||||
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
|
||||
# AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
|
||||
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
|
||||
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
|
||||
# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
||||
# PERFORMANCE OF THIS SOFTWARE.
|
||||
|
||||
# $Id: sort-options.pl,v 1.3 2007/09/24 23:46:48 tbox Exp $
|
||||
|
||||
sub sortlevel() {
|
||||
my @options = ();
|
||||
my $fin = "";
|
||||
my $i = 0;
|
||||
while (<>) {
|
||||
if (/^\s*};$/) {
|
||||
$fin = $_;
|
||||
# print 2, $_;
|
||||
last;
|
||||
}
|
||||
next if (/^$/);
|
||||
if (/{$/) {
|
||||
# print 3, $_;
|
||||
my $sec = $_;
|
||||
push(@options, $sec . sortlevel());
|
||||
} else {
|
||||
push(@options, $_);
|
||||
# print 1, $_;
|
||||
}
|
||||
$i++;
|
||||
}
|
||||
my $result = "";
|
||||
foreach my $i (sort @options) {
|
||||
$result = ${result}.${i};
|
||||
$result = $result."\n" if ($i =~ /^[a-z]/i);
|
||||
# print 5, ${i};
|
||||
}
|
||||
$result = ${result}.${fin};
|
||||
return ($result);
|
||||
}
|
||||
|
||||
print sortlevel();
|
||||
@@ -15,7 +15,7 @@
|
||||
* PERFORMANCE OF THIS SOFTWARE.
|
||||
*/
|
||||
|
||||
/* $Id: resolver.c,v 1.284.18.64 2007/10/31 05:14:59 marka Exp $ */
|
||||
/* $Id: resolver.c,v 1.284.18.66 2007/11/01 13:53:27 shane Exp $ */
|
||||
|
||||
/*! \file */
|
||||
|
||||
@@ -823,12 +823,12 @@ fctx_sendevents(fetchctx_t *fctx, isc_result_t result) {
|
||||
if (fctx->res->spillat > fctx->res->spillatmax &&
|
||||
fctx->res->spillatmax != 0)
|
||||
fctx->res->spillat = fctx->res->spillatmax;
|
||||
logit = ISC_TRUE;
|
||||
isc_interval_set(&i, 20 * 60, 0);
|
||||
result = isc_timer_reset(fctx->res->spillattimer,
|
||||
isc_timertype_ticker, NULL,
|
||||
&i, ISC_TRUE);
|
||||
RUNTIME_CHECK(result == ISC_R_SUCCESS);
|
||||
logit = ISC_TRUE;
|
||||
}
|
||||
UNLOCK(&fctx->res->lock);
|
||||
if (logit)
|
||||
|
||||
6
version
6
version
@@ -1,4 +1,4 @@
|
||||
# $Id: version,v 1.29.134.17 2007/10/31 02:59:58 marka Exp $
|
||||
# $Id: version,v 1.29.134.18 2007/11/19 15:25:23 each Exp $
|
||||
#
|
||||
# This file must follow /bin/sh rules. It is imported directly via
|
||||
# configure.
|
||||
@@ -6,5 +6,5 @@
|
||||
MAJORVER=9
|
||||
MINORVER=4
|
||||
PATCHVER=2
|
||||
RELEASETYPE=rc
|
||||
RELEASEVER=2
|
||||
RELEASETYPE=
|
||||
RELEASEVER=
|
||||
|
||||
Reference in New Issue
Block a user