Merge branch '2608-stale-answer-client-timeout-default-off' into 'main'

Change default stale-answer-client-timeout to off

Closes #2608

See merge request isc-projects/bind9!4862

CHANGES

@@ -1,3 +1,6 @@
+5611.	[func]		Set "stale-answer-client-timeout" to "off" by default.
+			[GL #2608]
+
 5610.	[bug]		Prevent a crash which could happen when a lookup
 			triggered by "stale-answer-client-timeout" was attempted
 			right after recursion for a client query finished.

bin/named/config.c

@@ -196,7 +196,7 @@ options {\n\
 	servfail-ttl 1;\n\
 #	sortlist <none>\n\
 	stale-answer-enable false;\n\
-	stale-answer-client-timeout 1800; /* in milliseconds */\n\
+	stale-answer-client-timeout off;\n\
 	stale-answer-ttl 30; /* 30 seconds */\n\
 	stale-cache-enable false;\n\
 	stale-refresh-time 30; /* 30 seconds */\n\

bin/tests/system/serve-stale/ns1/named1.conf.in

@@ -30,7 +30,6 @@ options {
 	max-stale-ttl 3600;
 	stale-answer-ttl 4;
 	stale-answer-enable yes;
-	stale-answer-client-timeout disabled;
 	stale-cache-enable yes;
 	stale-refresh-time 30;
 	servfail-ttl 0;

bin/tests/system/serve-stale/ns1/named2.conf.in

@@ -30,7 +30,6 @@ options {
 	max-stale-ttl 20;
 	stale-answer-ttl 3;
 	stale-answer-enable yes;
-	stale-answer-client-timeout disabled;
 	stale-cache-enable yes;
 	servfail-ttl 0;
 };

bin/tests/system/serve-stale/ns1/named3.conf.in

@@ -30,7 +30,6 @@ options {
 	max-stale-ttl 20;
 	stale-answer-ttl 3;
 	stale-answer-enable yes;
-	stale-answer-client-timeout disabled;
 	stale-cache-enable yes;
 	stale-refresh-time 0;
 	servfail-ttl 0;

bin/tests/system/serve-stale/ns3/named2.conf.in

@@ -37,6 +37,7 @@ options {
 	stale-cache-enable yes;
 	stale-answer-ttl 3;
 	stale-refresh-time 0;
+	stale-answer-client-timeout 1800;
 	max-stale-ttl 3600;
 	resolver-query-timeout 10;
 };

bin/tests/system/serve-stale/ns3/named3.conf.in

@@ -36,7 +36,6 @@ options {
 	stale-answer-enable yes;
 	stale-cache-enable yes;
 	stale-answer-ttl 3;
-	stale-answer-client-timeout off;
 	stale-refresh-time 0;
 	max-stale-ttl 3600;
 	resolver-query-timeout 10;

bin/tests/system/serve-stale/ns3/named6.conf.in

@@ -36,7 +36,6 @@ options {
 	stale-answer-enable no;
 	stale-cache-enable yes;
 	stale-answer-ttl 3;
-	stale-answer-client-timeout disabled;
 	stale-refresh-time 4;
 	resolver-query-timeout 10;
 	fetches-per-zone 1 fail;

bin/tests/system/serve-stale/ns3/named7.conf.in

@@ -40,7 +40,6 @@ options {
 	stale-answer-enable yes;
 	stale-cache-enable yes;
 	stale-answer-ttl 3;
-	stale-answer-client-timeout disabled;
 	stale-refresh-time 4;
 	resolver-query-timeout 10;
 	fetches-per-zone 1 fail;

bin/tests/system/serve-stale/tests.sh

@@ -1573,10 +1573,10 @@ grep -F "#NXDOMAIN" ns5/named.stats.$n.cachedb > /dev/null && ret=1
 status=$((status+ret))
 if [ $ret != 0 ]; then echo_i "failed"; fi
 
-########################################################
+################################################
-# Test for stale-answer-client-timeout (default 1.8s). #
+# Test for stale-answer-client-timeout (1.8s). #
-########################################################
+################################################
-echo_i "test stale-answer-client-timeout (default 1.8)"
+echo_i "test stale-answer-client-timeout (1.8)"
 
 n=$((n+1))
 echo_i "updating ns3/named.conf ($n)"

doc/arm/reference.rst

@@ -1856,18 +1856,21 @@ Boolean Options
    log category.
 
 ``stale-answer-client-timeout``
-   This option defines the amount of time ``named`` waits before attempting to
+   This option defines the amount of time (in milliseconds) that ``named``
-   answer the query with a stale RRset from cache. If a stale answer is found,
+   waits before attempting to answer the query with a stale RRset from cache.
-   ``named`` continues the ongoing fetches, attempting to refresh the RRset in
+   If a stale answer is found, ``named`` continues the ongoing fetches,
-   cache until the ``resolver-query-timeout`` interval is reached.
+   attempting to refresh the RRset in cache until the
+   ``resolver-query-timeout`` interval is reached.
 
-   The default value is ``1800`` (in milliseconds) and the maximum value is
+   This option is off by default, which is equivalent to setting it to
-   bounded to ``resolver-query-timeout`` minus one second. A value of ``0``
+   ``off`` or ``disabled``. It also has no effect if ``stale-answer-enable``
-   immediately returns a cached RRset if available, and still attempts a refresh
+   is disabled.
-   of the data in cache.
 
-   The option can be disabled by setting the value to ``off`` or ``disabled``.
+   The maximum value for this option is ``resolver-query-timeout`` minus
-   It also has no effect if ``stale-answer-enable`` is disabled.
+   one second. The minimum value, ``0``, causes a cached RRset to be
+   immediately returned if it is available while still attempting to
+   refresh the data in cache. :rfc:`8767` recommends a value of ``1800``
+   (milliseconds).
 
 ``stale-cache-enable``
    If ``yes``, enable the retaining of "stale" cached answers.  Default ``no``.

doc/notes/notes-current.rst

@@ -41,6 +41,10 @@ Feature Changes
   9.17.2, but it was not included in the release notes at the time.
   [GL #2607]
 
+- The default value for the ``stale-answer-client-timeout`` option was
+  changed from ``1800`` (ms) to ``off``. The default value may be
+  changed again in future releases as this feature matures. [GL #2608]
+
 Bug Fixes
 ~~~~~~~~~