ComputerSurge/bind9
3
0
Fork 0
Code Pull Requests 1 Activity
Files
f6ea2b1d09668564c764e5d32ada7652068f0562
bind9/doc/rfc/rfc6168.txt
Evan Hunt f2ea8c2f96 [master] updated published drafts
2014-02-14 08:53:06 -08:00

956 lines
36 KiB
Plaintext
Raw Blame History

This file contains invisible Unicode characters
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
Internet Engineering Task Force (IETF) W. Hardaker
Request for Comments: 6168 Sparta, Inc.
Category: Informational May 2011
ISSN: 2070-1721
Requirements for Management of Name Servers for the DNS
Abstract
Management of name servers for the Domain Name System (DNS) has
traditionally been done using vendor-specific monitoring,
configuration, and control methods. Although some service monitoring
platforms can test the functionality of the DNS itself, there is not
an interoperable way to manage (monitor, control, and configure) the
internal aspects of a name server itself.
This document discusses the requirements of a management system for
name servers and can be used as a shopping list of needed features
for such a system.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6168.
Hardaker Informational [Page 1]
RFC 6168 Name Server Management Requirements May 2011
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Hardaker Informational [Page 2]
RFC 6168 Name Server Management Requirements May 2011
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 4
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Document Layout and Requirements . . . . . . . . . . . . . 5
2. Management Architecture Requirements . . . . . . . . . . . . . 5
2.1. Expected Deployment Scenarios . . . . . . . . . . . . . . 5
2.1.1. Zone Size Constraints . . . . . . . . . . . . . . . . 6
2.1.2. Name Server Discovery . . . . . . . . . . . . . . . . 6
2.1.3. Configuration Data Volatility . . . . . . . . . . . . 6
2.1.4. Protocol Selection . . . . . . . . . . . . . . . . . . 6
2.1.5. Common Data Model . . . . . . . . . . . . . . . . . . 6
2.1.6. Operational Impact . . . . . . . . . . . . . . . . . . 7
2.2. Name Server Types . . . . . . . . . . . . . . . . . . . . 7
3. Management Operation Types . . . . . . . . . . . . . . . . . . 7
3.1. Control Requirements . . . . . . . . . . . . . . . . . . . 8
3.1.1. Needed Control Operations . . . . . . . . . . . . . . 8
3.1.2. Asynchronous Status Notifications . . . . . . . . . . 8
3.2. Configuration Requirements . . . . . . . . . . . . . . . . 9
3.2.1. Served Zone Modification . . . . . . . . . . . . . . . 9
3.2.2. Trust Anchor Management . . . . . . . . . . . . . . . 9
3.2.3. Security Expectations . . . . . . . . . . . . . . . . 9
3.2.4. TSIG Key Management . . . . . . . . . . . . . . . . . 9
3.2.5. DNS Protocol Authorization Management . . . . . . . . 10
3.3. Monitoring Requirements . . . . . . . . . . . . . . . . . 10
3.4. Alarm and Event Requirements . . . . . . . . . . . . . . . 11
4. Security Requirements . . . . . . . . . . . . . . . . . . . . 11
4.1. Authentication . . . . . . . . . . . . . . . . . . . . . . 11
4.2. Integrity Protection . . . . . . . . . . . . . . . . . . . 11
4.3. Confidentiality . . . . . . . . . . . . . . . . . . . . . 11
4.4. Authorization . . . . . . . . . . . . . . . . . . . . . . 12
4.5. Solution Impacts on Security . . . . . . . . . . . . . . . 12
5. Other Requirements . . . . . . . . . . . . . . . . . . . . . . 12
5.1. Extensibility . . . . . . . . . . . . . . . . . . . . . . 12
5.1.1. Vendor Extensions . . . . . . . . . . . . . . . . . . 13
5.1.2. Extension Identification . . . . . . . . . . . . . . . 13
5.1.3. Name-Space Collision Protection . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Document History . . . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Deployment Scenarios . . . . . . . . . . . . . . . . 16
A.1. Non-Standard Zones . . . . . . . . . . . . . . . . . . . . 16
A.2. Redundancy Sharing . . . . . . . . . . . . . . . . . . . . 16
A.3. DNSSEC Management . . . . . . . . . . . . . . . . . . . . 17
Hardaker Informational [Page 3]
RFC 6168 Name Server Management Requirements May 2011
1. Introduction
Management of name servers for the Domain Name System (DNS) [RFC1034]
[RFC1035] has traditionally been done using vendor-specific
monitoring, configuration, and control methods. Although some
service monitoring platforms can test the functionality of the DNS
itself, there is not an interoperable way to manage (monitor,
control, and configure) the internal aspects of a name server itself.
Previous standardization work within the IETF resulted in the
creation of two SNMP MIB modules [RFC1611] [RFC1612], but they failed
to achieve significant implementation and deployment. The perceived
reasons behind the failure for the two MIB modules are documented in
[RFC3197].
This document discusses the requirements of a management system for
name servers and can be used as a shopping list of needed features
for such a system. This document only discusses requirements for
managing the name server component of a system -- not other elements
of the system itself.
Specifically out of scope for this document are requirements
associated with the management of stub resolvers. It is not the
intent of this document to document stub resolver requirements,
although some of the requirements listed are applicable to stub
resolvers as well.
The task of creating a management system for managing DNS servers is
not expected to be a small one. It is likely that components of the
solution will need to be designed in parts over time; these
requirements take this into consideration. In particular,
Section 5.1 discusses the need for future extensibility of the base
management solution. This document is intended to be a roadmap
towards a desired outcome and is not intended to define an "all-or-
nothing" system. Successful interoperable management of name
servers, even in part, is expected to be beneficial to network
operators compared to the entirely custom solutions that are used at
the time of this writing.
1.1. Requirements Notation
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 [RFC2119].
Hardaker Informational [Page 4]
RFC 6168 Name Server Management Requirements May 2011
1.2. Terminology
This document is consistent with the terminology defined in Section 2
of [RFC4033]. Additional terminology needed for this document is
described below:
Name Server: When we are discussing servers that don't fall into a
more specific type of server category defined in other documents,
this document will refer to them generically as "name servers".
In particular, "name servers" can be considered to be any valid
combination of authoritative, recursive, validating, or security-
aware. The more specific name server labels will be used when
this document refers only to a specific type of server. However,
the term "name server", in this document, will not include stub
resolvers.
1.3. Document Layout and Requirements
This document is written so that each numbered section will contain
only a single requirement if it contains one at all. Each
requirement will contain needed wording from the terminology
described in Section 1.1. Subsections, however, might exist with
additional related requirements. The document is laid out in this
way so that a specific requirement can be uniquely referred to using
the section number itself and the document version from which it
came.
2. Management Architecture Requirements
This section discusses requirements that reflect the needs of the
expected deployment environments.
2.1. Expected Deployment Scenarios
DNS zones vary greatly in the type of content published within them.
Name servers, too, are deployed with a wide variety of configurations
to support the diversity of the deployed content. It is important
that a management solution trying to meet the criteria specified in
this document consider supporting the largest number of potential
deployment cases as possible. Further deployment scenarios that are
not used as direct examples of specific requirements are listed in
Appendix A.
Hardaker Informational [Page 5]
RFC 6168 Name Server Management Requirements May 2011
2.1.1. Zone Size Constraints
The management solution MUST support both name servers that are
serving a small number of potentially very large zones (e.g., Top
Level Domains (TLDs)) as well as name servers that are serving a very
large number of small zones. Both deployment scenarios are common.
2.1.2. Name Server Discovery
Large enterprise network deployments may contain multiple name
servers operating within the boundaries of the enterprise network.
These name servers may each be serving multiple zones both in and out
of the parent enterprise's zone. Finding and managing large numbers
of name servers would be a useful feature of the resulting management
solution. The management solution MAY support the ability to
discover previously unknown instances of name servers operating
within a deployed network.
2.1.3. Configuration Data Volatility
Configuration data is defined as data that relates only to the
configuration of a server and the zones it serves. It specifically
does not include data from the zone contents that is served through
DNS itself. The solution MUST support servers that remain statically
configured over time as well as servers that have numerous zones
being added and removed within an hour. Both deployment scenarios
are common.
2.1.4. Protocol Selection
There are many requirements in this document for many different types
of management operations (see Section 3 for further details). It is
possible that no one protocol will ideally fill all the needs of the
requirements listed in this document, and thus multiple protocols
might be needed to produce a completely functional management system.
Multiple protocols might be used to create the complete management
solution, but the solution SHOULD require only one.
2.1.5. Common Data Model
Defining a standardized protocol (or set of protocols) to use for
managing name servers would be a step forward in achieving an
interoperable management solution. However, just defining a protocol
to use by itself would not achieve the entire end goal of a complete
interoperable management solution. Devices also need to represent
their internal management interface using a common management data
model. The solution MUST create a common data model that management
stations can make use of when sending or collecting data from a
Hardaker Informational [Page 6]
RFC 6168 Name Server Management Requirements May 2011
managed device so it can successfully manage equipment from vendors
as if they were generic DNS servers. This common data model is
needed for the operations discussion in Section 3. Note that this
does not preclude the fact that name server vendors might provide
additional management infrastructure beyond a base management
specification, as discussed further in Section 5.1.
2.1.6. Operational Impact
It is impossible to add new features to an existing server (such as
the inclusion of a management infrastructure) and not impact the
existing service and/or server in some fashion. At a minimum, for
example, more memory, disk, and/or CPU resources will be required to
implement a new management system. However, the impact to the
existing DNS service MUST be minimized since the DNS service itself
is still the primary service to be offered by the modified name
server. The management solution MUST NOT result in an increase of
the number of unhandled DNS requests.
2.2. Name Server Types
There are multiple ways in which name servers can be deployed. Name
servers can take on any of the following roles:
o Master Servers
o Slave Servers
o Recursive Servers
The management solution SHOULD support all of these types of name
servers as they are all equally important. Note that "Recursive
Servers" can be further broken down by the security sub-roles they
might implement, as defined in section 2 of [RFC4033]. These sub-
roles are also important to support within any management solution.
As stated earlier, the management of stub resolvers is considered out
of scope for this document.
3. Management Operation Types
Management operations can traditionally be broken into four
categories:
o Control
o Configuration
Hardaker Informational [Page 7]
RFC 6168 Name Server Management Requirements May 2011
o Health and Monitoring
o Alarms and Events
This section discusses detailed requirements for each of these four
management categories.
3.1. Control Requirements
The management solution MUST be capable of performing basic service
control operations.
3.1.1. Needed Control Operations
These operations SHOULD include, at a minimum, the following
operations:
o Starting the name server
o Reloading the service configuration
o Reloading all of the zone data
o Reloading individual zone data sets
o Restarting the name server
o Stopping the name server
Note that no restriction is placed on how the management system
implements these operations. In particular, at least "starting the
name server" will require a minimal management system component to
exist independently of the name server itself.
3.1.2. Asynchronous Status Notifications
Some control operations might take a long time to complete. As an
example, some name servers take a long time to perform reloads of
large zones. Because of these timing issues, the management solution
SHOULD take this into consideration and offer a mechanism to ease the
burden associated with awaiting the status of a long-running command.
This could, for example, result in the use of asynchronous
notifications for returning the status of a long-running task, or it
might require the management station to poll for the status of a
given task using monitoring commands. These and other potential
solutions need to be evaluated carefully to select one that balances
the result delivery needs with the perceived implementation costs.
Hardaker Informational [Page 8]
RFC 6168 Name Server Management Requirements May 2011
Also, see the related discussion in Section 3.4 on notification
messages for supporting delivery of alarm and event messages.
3.2. Configuration Requirements
Many features of name servers need to be configured before the server
can be considered functional. The management solution MUST be able
to provide name servers with configuration data. The most important
data to be configured, for example, is the served zone data itself.
3.2.1. Served Zone Modification
The ability to add, modify, and delete zones being served by name
servers is needed. Although there are already solutions for zone
content modification (such as Dynamic DNS (DDNS) [RFC2136] [RFC3007],
full zone transfer (AXFR) [RFC5936], and incremental zone transfer
(IXFR) [RFC1995]) that might be used as part of the final management
solution, the management system SHOULD still be able to create a new
zone (with enough minimal data to allow the other mechanisms to
function as well) and to delete a zone. This might be, for example,
a management operation that allows for the creation of at least the
initial SOA (Start of Authority) record for a new zone, since that is
the minimum amount of zone data needed for the other operations to
function.
3.2.2. Trust Anchor Management
The solution SHOULD support the ability to add, modify, and delete
trust anchors that are used by DNS Security (DNSSEC) [RFC4033]
[RFC4034] [RFC4035] [RFC4509] [RFC5011] [RFC5155]. These trust
anchors might be configured using the data from the DNSKEY Resource
Records (RRs) themselves or by using Delegation Signer (DS)
fingerprints.
3.2.3. Security Expectations
DNSSEC validating resolvers need to make policy decisions about the
requests being processed. For example, they need to be configured
with a list of zones expected to be secured by DNSSEC. The
management solution SHOULD be able to add, modify, and delete
attributes of DNSSEC security policies.
3.2.4. TSIG Key Management
TSIG [RFC2845] allows transaction-level authentication of DNS
traffic. The management solution SHOULD be able to add, modify, and
delete TSIG keys known to the name server.
Hardaker Informational [Page 9]
RFC 6168 Name Server Management Requirements May 2011
3.2.5. DNS Protocol Authorization Management
The management solution SHOULD have the ability to add, modify, and
delete authorization settings for the DNS protocols itself. Do not
confuse this with the ability to manage the authorization associated
with the management protocol itself, which is discussed later in
Section 4.4. There are a number of authorization settings that are
used by a name server. Example authorization settings that the
solution might need to cover are:
o Access to operations on zone data (e.g., DDNS)
o Access to certain zone data from certain sources (e.g., from
particular network subnets)
o Access to specific DNS protocol services (e.g., recursive service)
Note: the above list is expected to be used as a collection of
examples and is not a complete list of needed authorization
protections.
3.3. Monitoring Requirements
Monitoring is the process of collecting aspects of the internal state
of a name server at a given moment in time. The solution MUST be
able to monitor the health of a name server to determine its
operational status, load, and other internal attributes. Example
parameters that the solution might need to collect and analyze are:
o Number of requests sent, responses sent, number of errors, average
response latency, and other performance counters
o Server status (e.g., "serving data", "starting up", "shutting
down", etc.)
o Access control violations
o List of zones being served
o Detailed statistics about clients interacting with the name server
(e.g., top 10 clients requesting data).
Note: the above list is expected to be used as a collection of
examples and is not a complete list of needed monitoring operations.
In particular, some monitoring statistics are expected to be
computationally or resource expensive and are considered to be "nice
to have" as opposed to "necessary to have".
Hardaker Informational [Page 10]
RFC 6168 Name Server Management Requirements May 2011
3.4. Alarm and Event Requirements
Events occurring at the name server that trigger alarm notifications
can quickly inform a management station about critical issues. A
management solution SHOULD include support for delivery of alarm
conditions.
Example alarm conditions might include:
o The server's status is changing (e.g., it is starting up,
reloading configuration, restarting or shutting down).
o A needed resource (e.g., memory or disk space) is exhausted or
nearing exhaustion.
o An authorization violation was detected.
o The server has not received any data traffic (e.g., DNS requests
or NOTIFYs) recently (aka the "lonely warning"). This condition
might indicate a problem with the server's deployment.
o The number of errors has exceeded a configured threshold.
4. Security Requirements
The management solution will need to be appropriately secured against
attacks on the management infrastructure.
4.1. Authentication
The solution MUST support mutual authentication. The management
client needs to be assured that the management operations are being
transferred to and from the correct name server. The managed name
server needs to authenticate the system that is accessing the
management infrastructure within itself.
4.2. Integrity Protection
Management operations MUST be protected from modification while in
transit from the management client to the server.
4.3. Confidentiality
The management solution MUST support message confidentiality. The
potential transfer of sensitive configuration is expected (such as
TSIG keys or security policies). The solution does not, however,
necessarily need to provide confidentiality to data that would
normally be carried without confidentiality by the DNS system itself.
Hardaker Informational [Page 11]
RFC 6168 Name Server Management Requirements May 2011
4.4. Authorization
The solution SHOULD provide an authorization model capable of
selectively authorizing individual management requests for any
management protocols it introduces to the completed system. This
authorization differs from the authorization previously discussed in
Section 3.2.5 in that this requirement is concerned solely with
authorization of the management system itself.
There are a number of authorization settings that might be used by a
managed system to determine whether the managing entity has
authorization to perform the given management task. Example
authorization settings that the solution might need to cover are:
o Access to the configuration that specifies which zones are to be
served
o Access to the management system infrastructure
o Access to other control operations
o Access to other configuration operations
o Access to monitoring operations
Note: the above list is expected to be used as a collection of
examples and is not a complete list of needed authorization
protections.
4.5. Solution Impacts on Security
The solution MUST minimize the security risks introduced to the
complete name server system. It is impossible to add new
infrastructure to a server and not impact the security in some
fashion as the introduction of a management protocol alone will
provide a new avenue for potential attack. Although the added
management benefits will be worth the increased risks, the solution
still needs to minimize this impact as much as possible.
5. Other Requirements
5.1. Extensibility
The management solution is expected to change and expand over time as
lessons are learned and new DNS features are deployed. Thus, the
solution MUST be flexible and able to accommodate new future
management operations. The solution might, for example, make use of
protocol versioning or capability description exchanges to ensure
Hardaker Informational [Page 12]
RFC 6168 Name Server Management Requirements May 2011
that management stations and name servers that weren't written to the
same specification version can still interoperate to the best of
their combined ability.
5.1.1. Vendor Extensions
It MUST be possible for vendors to extend the standardized management
model with vendor-specific extensions to support additional features
offered by their products.
5.1.2. Extension Identification
It MUST be possible for a management station to understand which
parts of returned data are specific to a given vendor or other
standardized extension. The data returned needs to be appropriately
marked, through the use of name spaces or similar mechanisms, to
ensure that the base management model data can be logically separated
from the extension data without needing to understand the extension
data itself.
5.1.3. Name-Space Collision Protection
It MUST be possible to protect against multiple extensions
conflicting with each other. The use of name-space protection
mechanisms for communicated management variables is common practice
to protect against such problems. Name-space identification
techniques also frequently solve the "Extension Identification"
requirement discussed in Section 5.1.2.
6. Security Considerations
Any management protocol for which conformance to this document is
claimed needs to fully support the criteria discussed in Section 4 in
order to protect the management infrastructure itself. The DNS is a
core Internet service, and management traffic that protects it could
be the target of attacks designed to subvert that service. Because
the management infrastructure will be adding additional interfaces to
that service, it is critical that the management infrastructure
support adequate protections against network attacks.
7. Document History
A requirement-gathering discussion was held at the December 2007 IETF
meeting in Vancouver, BC, Canada, and a follow-up meeting was held at
the March 2008 IETF meeting in Philadelphia. This document is a
compilation of the results of those discussions as well as
discussions on the DCOMA mailing list.
Hardaker Informational [Page 13]
RFC 6168 Name Server Management Requirements May 2011
8. Acknowledgments
This document is the result of discussions within the DCOMA design
team chaired by Jaap Akkerhuis. This team consisted of a large
number of people, all of whom provided valuable insight and input
into the discussions surrounding name server management. The text of
this document was written from notes taken during meetings as well as
from contributions sent to the DCOMA mailing list. This work
documents the consensus of the DCOMA design team.
In particular, the following team members contributed significantly
to the text in the document:
Stephane Bortzmeyer
Stephen Morris
Phil Regnauld
Further editing contributions and wording suggestions were made by
Alfred Hoenes and Doug Barton.
9. References
9.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995,
August 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997.
[RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS
(TSIG)", RFC 2845, May 2000.
[RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic
Update", RFC 3007, November 2000.
Hardaker Informational [Page 14]
RFC 6168 Name Server Management Requirements May 2011
[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.
[RFC4509] Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer
(DS) Resource Records (RRs)", RFC 4509, May 2006.
[RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC)
Trust Anchors", RFC 5011, September 2007.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, March 2008.
[RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol
(AXFR)", RFC 5936, June 2010.
9.2. Informative References
[RFC1611] Austein, R. and J. Saperia, "DNS Server MIB Extensions",
RFC 1611, May 1994.
[RFC1612] Austein, R. and J. Saperia, "DNS Resolver MIB Extensions",
RFC 1612, May 1994.
[RFC2182] Elz, R., Bush, R., Bradner, S., and M. Patton, "Selection
and Operation of Secondary DNS Servers", BCP 16, RFC 2182,
July 1997.
[RFC3197] Austein, R., "Applicability Statement for DNS MIB
Extensions", RFC 3197, November 2001.
Hardaker Informational [Page 15]
RFC 6168 Name Server Management Requirements May 2011
Appendix A. Deployment Scenarios
This appendix documents some additional deployment scenarios that
have been traditionally difficult to manage. They are provided as
guidance to protocol developers as data points of real-world name
server management problems.
A.1. Non-Standard Zones
If an organization uses non-standard zones (for example a purely
local TLD), synchronizing all the name servers for these zones is
usually a time-consuming task. It is made worse when two
organizations with conflicting zones merge. This situation is not a
recommended deployment scenario (and is even heavily discouraged),
but it is, unfortunately, seen in the wild.
It is typically implemented using "forwarding" zones. But there is
no way to ensure automatically that all the resolvers have the same
set of zones to forward at any given time. New zones might be added
to a local forwarding recursive server, for example, without
modifying the rest of the deployed forwarding servers. It is hoped
that a management solution that could handle the configuration of
zone forwarding would finally allow management of servers deployed in
this fashion.
A.2. Redundancy Sharing
For reliability reasons, it is recommended that zone operators follow
the guidelines documented in [RFC2182], which recommends that
multiple name servers be configured for each zone and that the name
servers be separated both physically and via connectivity routes. A
common solution is to establish DNS-serving partnerships: "I'll host
your zones and you'll host mine". Both entities benefit from
increased DNS reliability via the wider service distribution. This
frequently occurs between cooperating but otherwise unrelated
entities (such as between two distinct companies) as well as between
affiliated organizations (such as between branch offices within a
single company).
The configuration of these relationships are currently required to be
manually configured and maintained. Changes to the list of zones
that are cross-hosted are manually negotiated between the cooperating
network administrators and configured by hand. A management protocol
with the ability to provide selective authorization, as discussed in
Section 4.4, would solve many of the management difficulties between
cooperating organizations.
Hardaker Informational [Page 16]
RFC 6168 Name Server Management Requirements May 2011
A.3. DNSSEC Management
There are many different DNSSEC deployment strategies that may be
used for mission-critical zones. The following list describes some
example deployment scenarios that might warrant different management
strategies.
All contents and DNSSEC keying information controlled and operated
by a single organization
Zone contents controlled and operated by one organization, all
DNSSEC keying information controlled and operated by a second
organization.
Zone contents controlled and operated by one organization, zone
signing keys (ZSKs) controlled and operated by a second
organization, and key signing keys (KSKs) controlled and operated
by a third organization.
Although this list is not exhaustive in the potential ways that zone
data can be divided up, it should be sufficient to illustrate the
potential ways in which zone data can be controlled by multiple
entities.
The end result of all of these strategies, however, will be the same:
a live zone containing DNSSEC-related resource records. Many of the
above strategies are merely different ways of preparing a zone for
serving. A management solution that includes support for managing
DNSSEC zone data may wish to take into account these potential
management scenarios.
Author's Address
Wes Hardaker
Sparta, Inc.
P.O. Box 382
Davis, CA 95617
US
Phone: +1 530 792 1913
EMail: ietf@hardakers.net
Hardaker Informational [Page 17]
View Git Blame Copy Permalink