clarify serve-stale documentation, and add a floor for max-stale-ttl

- added a 1-second floor to max-stale-ttl similar to stale-answer-ttl;
  if set to 0, it will be silently updated to 1.
- fixed the ARM entry on max-stale-ttl, which incorrectly suggested that
  the default was 0 instead of 1 week.
- clarified rndc serve-stale documentation.
This commit is contained in:
Evan Hunt
2018-05-25 22:00:37 -07:00
parent 58ad54e7a1
commit d1ca21d50a
3 changed files with 58 additions and 37 deletions

View File

@@ -5349,12 +5349,13 @@ options {
Specifies the TTL to be returned on stale answers.
The default is 1 second. The minimum allowed is
also 1 second; a value of 0 will be updated silently
to 1 second. For stale answers to be returned,
they must be enabled (either in the configuration file
using <command>stale-answer-enable</command> or via
<command>rndc</command>), and
<option>max-stale-ttl</option> must be set to a
nonzero value.
to 1 second.
</para>
<para>
For stale answers to be returned, they must be enabled,
either in the configuration file using
<command>stale-answer-enable</command> or via
<command>rndc serve-stale on</command>.
</para>
</listitem>
</varlistentry>
@@ -6098,18 +6099,28 @@ options {
<term><command>stale-answer-enable</command></term>
<listitem>
<para>
Enable the returning of stale answers when the
nameservers for the zone are not answering. This
is off by default, but can be enabled/disabled via
<command>rndc serve-stale on</command> and
<command>rndc serve-stale off</command>, which
override the <filename>named.conf</filename>
setting. <command>rndc serve-stale reset</command>
Enable the returning of "stale" cached answers when
the nameservers for a zone are not answering. The
default is not to return stale answers.
</para>
<para>
Stale answers can also be enabled or disabled at
runtime via <command>rndc serve-stale on</command> or
<command>rndc serve-stale off</command>; these
override the configured setting.
<command>rndc serve-stale reset</command>
restores the setting to the one specified in
<filename>named.conf</filename>. Note that
reloading or reconfiguring <command>named</command>
will not re-enable serving of stale records if they
have been disabled via <command>rndc</command>.
<filename>named.conf</filename>. Note that if
stale answers have been disabled by <command>rndc</command>,
then they cannot be re-enabled by reloading or
reconfiguring <command>named</command>;
they must be re-enabled with
<command>rndc serve-stale on</command>,
or the server must be restarted.
</para>
<para>
Information about stale answers is logged under
the <command>serve-stale</command> log category.
</para>
</listitem>
</varlistentry>
@@ -8901,19 +8912,21 @@ avoid-v6-udp-ports { 40000; range 50000 60000; };
<term><command>max-stale-ttl</command></term>
<listitem>
<para>
Sets the maximum time for which the server will
If stale answers are enabled,
<command>max-stale-ttl</command>
sets the maximum time for which the server will
retain records past their normal expiry to
return them as stale records when the servers
for those records are not reachable. The default
is to not retain the record.
for those records are not reachable.
The default is 1 week. The minimum allowed is
1 second; a value of 0 will be updated silently
to 1 second.
</para>
<para>
<command>rndc serve-stale</command> can be used
to disable and re-enable the serving of stale
records at runtime. Reloading or reconfiguring
<command>named</command> will not re-enable serving
of stale records if they have been disabled via
<command>rndc</command>.
For stale answers to be returned, they must be enabled,
either in the configuration file using
<command>stale-answer-enable</command> or via
<command>rndc serve-stale on</command>.
</para>
</listitem>
</varlistentry>