On Thu, 16 Aug 2007 10:40:49 EDT, Tuc at T-B-O-H said:
Mail to RR users is getting refused due to PTR issues. I contacted RR and explained that yea, one of our 2 DNS servers for the IN-ADDR.ARPA is down, but the other is fine. They said that I should either get the DNS server back up (Which of course is already being worked on, was the minute it went down) or delete it from ARIN IN-ADDR.ARPA records.
Isn't the whole point of multiple DNS servers that if one is down the other can still answer queries? Or am I missing something here???
Depends exactly what your "down" server is doing. If it's totally not answering, the resolver at RR should silently fall back and try the other one. It gets more interesting if your "down" server is still answering queries, particlylarly if it's giving out "I never heard of it" answers with the authoritative bit set because it's blown out a zone. In that case, the RR resolver is within its rights to assume that your NS knows what it's talking about and believing it.