Hi, we are experiencing that our recursive resolver running BIND 9.9.9-P6 is sometimes apparently spuriously returning SERVAIL to certain queries.
I suspect this is related to expiry of entries from the cache, as this sort of error appears to occur more often for entries which are published with a low TTL, as in e.g. '1', e.g. some local admins have seen fit to publish cltrd012.mysql.db.uninett.no with a 1s TTL, and after rebuilding BIND with with --enable-querytrace I find these entries in the "client" log: client.log.15:09-Apr-2017 12:34:52.490 query client=0x7f7feb0dd000 thread=0x7f7ff7b92000 (cltrd005.pgsql.db.uninett.no/A): query_find: unexpected error after resuming: address not available client.log.15:09-Apr-2017 12:34:53.539 query client=0x7f7fe3404800 thread=0x7f7ff7b96000 (cltrd012.mysql.db.uninett.no/A): query_find: unexpected error after resuming: address not available client.log.15:09-Apr-2017 12:34:53.590 query client=0x7f7fe7302800 thread=0x7f7ff7b92000 (cltrd012.mysql.db.uninett.no/A): query_find: unexpected error after resuming: address not available etc. etc. Sometimes names with more sensible TTLs experience these failures as well: client.log.25:09-Apr-2017 04:55:10.194 query client=0x7f7fe9f14000 thread=0x7f7ff7b98000 (ns.uninett.no/AAAA): query_find: unexpected error after resuming: address not available After browsing the code a bit I thought that there was a lack of available FDs to BIND which triggered this, but I've bumped the system FD limit and BIND has been restarted and has all its 4096 FDs available, and I doubt that's the actual reason. This recursive resolver typically processes between 500 and 1000 queries/second. I tried googling the log message, but I could not find anything which exactly matched; the closest appeared to be the thread from June last year about "Issues resolving outlook.office365.org", but there I find another error message after the "after resuming", so maybe it's a different bug. I would also expect that 9.9.9-P6 is a version which succeeds the "next maintenance release" Mark was mentioning in that thread. Regards, - Håvard _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list [email protected] https://lists.isc.org/mailman/listinfo/bind-users
