On 31.7.2018 08:53, Zdenek Novy wrote:
  Hi,
 I would like to ask about the implementation of the Resource records in
 RRSet in KnotDNS.
 I have the domain with the three TXT record with same class IN for the
 same label ('@') and with the different TTLs. In nsd and bind DNS
 servers seems everything fine, but in KnotDNS I got the warning and error:
 knotd[551]: warning: [xxxxxxx.xxx.] zone loader, RRSet TTLs mismatched,
 node 'xxxxxxx.xxx.' (record type TXT)
 knotd[551]: error: [xxxxxxx.xxx.] zone loader, failed to load zone, file
 '/etc/knot/files/master.gen/xxxxxxx.xxx' (TTL mismatch)
 knotd[551]: error: [xxxxxxx.xxx.] failed to parse zonefile (failed)
 knotd[551]: error: [xxxxxxx.xxx.] zone event 'load' failed (failed)
 Is it a correct behavior and other DNS servers don't check it or is it a
 bug in KnotDNS? 
This behavior is correct according to standard
https://tools.ietf.org/html/rfc2181#section-5.2 :
   Consequently the use of differing TTLs in an RRSet is hereby
   deprecated, the TTLs of all RRs in an RRSet must be the same.
I suspect that other servers will silently clip TTL to one value but I
haven't checked that.
Petr Špaček  @  CZ.NIC
 Thank you for reply.
 Cheers,