This is Perfect Server Ubuntu 10.04. I recently changed DNS forwarders from my ISP-provided to a pair of the fastest (from here) public DNS sites: SpeakEasy and Google Public DNS. The ISP sites were about 5x slower and were returning advertising material for non-existent domains.
// Google Public DNS
I've always seen a number of DNS errors in the logs, like these from the ISP DNS servers:
DNS format error from 126.96.36.199#53 resolving dns1.name-services.com/AAAA: invalid response: 1 Time(s)
error (FORMERR) resolving 'dns3.name-services.com/AAAA/IN': 188.8.131.52#53: 17 Time(s)
error (network unreachable) resolving '184.108.40.206.zen.spamhaus.org/A/IN': 2001:7b8:3:1f:0:2:53:2#53: 1 Time(s)
error (unexpected RCODE REFUSED) resolving '220.127.116.11.in-addr.arpa/PTR/IN':
success resolving '18.104.22.168.bb.barracudacentral.org/A' (in 'bb.barracudacentral.org'?) after disabling EDNS: 1 Time(s)
but the number is small (< 50 per day) and there seems to be no impact.
After changing the DNS servers, I see a couple of hundred errors related to URIBL DNS queries (out of a 10.04 VM running ISPConfig 2.2.40 / SA) like these (many different domains overall):
error (unexpected RCODE REFUSED) resolving 'radisson.com.multi.uribl.com/A/IN': 22.214.171.124#53: 1 Time(s)
All of these were returned from the Google Public DNS server.
In addition, I see about the same number of these and similar:
error (network unreachable) resolving 'C.ROOT-SERVERS.NET/AAAA/IN': 2001:500:2f::f#53: 1 Time(s)
error (network unreachable) resolving 'k.gtld-servers.net/AAAA/IN': 2001:7fd::1#53: 1 Time(s)
error (network unreachable) resolving 'ns3.google.com/AAAA/IN': 2001:503:c27::2:30#53: 1 Time(s)
I'd like to clear this up on the server. Is this a symptom of 1) a problem with the local Bind installation; 2) a problem with SA / URIBL; 3) a problem with the public DNS servers; 4) not a problem other than syslog inflation?