.`stale-answer` now provides old cached records in case of DDoS attack
Previously, the Distributed Denial of Service (DDoS) attack caused the authoritative servers to fail with the SERVFAIL error. With this update, the `stale-answer` functionality provides the expired records until a fresh response is obtained.
To enable or disable the `serve-stale` feature, use either of these:
* Configuration file
* Remote control channel (rndc)
Description of problem:
Support for stale-answer-enable and others is missing. Allows responding from cache when authoritative servers are under attack or not responding.
Upstream change:
4700. [func] Serving of stale answers is now supported. This
allows named to provide stale cached answers when
the authoritative server is under attack.
See max-stale-ttl, stale-answer-enable,
stale-answer-ttl. [RT #44790]
First commit:
https://gitlab.isc.org/isc-projects/bind9/commit/df50751585b64f72d93ad665abf0f485c8941a3b
Check bug #1653111 comment #7 for more details.
Version-Release number of selected component (if applicable):
bind-9.11.4-14.P2.el8
Additional info:
Upstream has no support for stale cache in 9.11 ESV version, the feature was introduced in 9.12 version.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHSA-2020:1845
Description of problem: Support for stale-answer-enable and others is missing. Allows responding from cache when authoritative servers are under attack or not responding. Upstream change: 4700. [func] Serving of stale answers is now supported. This allows named to provide stale cached answers when the authoritative server is under attack. See max-stale-ttl, stale-answer-enable, stale-answer-ttl. [RT #44790] First commit: https://gitlab.isc.org/isc-projects/bind9/commit/df50751585b64f72d93ad665abf0f485c8941a3b Check bug #1653111 comment #7 for more details. Version-Release number of selected component (if applicable): bind-9.11.4-14.P2.el8 Additional info: Upstream has no support for stale cache in 9.11 ESV version, the feature was introduced in 9.12 version.