Hi, what does dns.sys.srvtest. return?
Ondrej -- Ondřej Surý (He/Him) [email protected] ADHD brain at work: I sometimes lose track of my inbox. Please feel free to send a gentle nudge if you're waiting on a reply! My working hours and your working hours may be different. Please do not feel obligated to reply outside your normal working hours. > On 24. 3. 2026, at 6:47, fitwateys <[email protected]> wrote: > > Hi, > I encountered a persistent issue in BIND 9.20.20 where the cache does not > refresh correctly when a domain changes from an A record to a CNAME record, > but only when stale-answer-client-timeout is set to 0.Environment > • BIND Version: 9.20.20 > • OS: openEuler 24.03 (LTS-SP1) > • Architecture: x86_64 > • Installation: Compiled from source > Configuration > bind > options { > directory "/var/named"; > listen-on port 53 { any; }; > listen-on-v6 port 53 { any; }; > allow-query { any; }; > recursion yes; > > max-cache-ttl 86400; > min-cache-ttl 3; > > stale-cache-enable yes; > max-stale-ttl 90000; > stale-answer-enable yes; > stale-answer-ttl 63; > stale-answer-client-timeout 0; // problematic when set to 0 > }; > Problem Description > When a domain changes from an A record to a CNAME (e.g., test.sys.srvtest), > BIND continues to return the stale A record from cache instead of refreshing > to obtain the new CNAME. > • Before change: > test.sys.srvtest. 120 IN A 127.0.0.130 > • After change: > test.sys.srvtest. 120 IN CNAME dns.sys.srvtest. > Even after the change, dig test.sys.srvtest returns: > text > test.sys.srvtest. 63 IN A 127.0.0.130 (stale) > > with the following EDNS option: > text > EDE: 3 (Stale Answer): (stale data prioritized over lookup) > This issue occurs only when stale-answer-client-timeout 0 is set. > If the line is commented out (default behavior), the cache refreshes > correctly and the CNAME record is returned.Expected Behavior > With stale-answer-client-timeout 0, BIND should still attempt to refresh the > cache and return the updated CNAME record after the TTL expires, rather than > persistently serving stale A data.Additional Information > This seems to be a regression or edge case related to how stale answers are > prioritized when the record type changes (A → CNAME) under aggressive > stale-answer-client-timeout settings. > Let me know if you need further details or a test environment. > Thanks! > -- > Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from > this list. -- Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list.
