> What are the situations (timeouts, FORMERR .. etc) to mark the server > as unable to speak EDNS0? (add_bad)
named tries to send a query with EDNS(0); if the query fails, it will try again with EDNS(0) but with the packet size limited to 512 bytes; and if that fails, it will try again without EDNS(0). If at that point it succeeds, then it memorizes the formula that worked: it won't try to use EDNS(0) again with that server for the duration of the server's TTL, or one day, whichever is shorter. > How can be server recovered again as EDNS0 capable? [...] > Only recovery was to flush cache. I don't think you need to flush the whole cache; 'rndc flushname <name>' will clear the entry for the affected name server, and should be sufficient. -- Evan Hunt -- e...@isc.org Internet Systems Consortium, Inc. _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users