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I'm trying to understand why one given DNS server is not resolving our domain correctly.

When I look up from this name server, a CNAME is correctly returned but there's no attached A record and the response status is NXDOMAIN. I understand that this could happen if the DNS server can not resolve the alias However, if I use the same DNS server and look up directly, I always get the correct A record.

When using any other DNS servers I've tested (different ISPs, Google DNS, Open DNS) our domain resolves correctly.

Given this situation, is there some possible problem in our DNS that could cause this? Or does it seem like this given DNS server is to blame? The DNS server in question is used by a lot of people and it seems more likely that the problem is caused by us, but I don't see how - any clues?

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The actual DNS record at issue would help, so we can examine the situation directly. – womble Aug 22 '12 at 9:59
The record we're looking up is – Martin Aug 22 '12 at 10:11
Might also help if you tell us what DNS server you're getting this result from... – HopelessN00b Aug 23 '12 at 17:47
Good point - the DNS server in question is – Martin Aug 24 '12 at 17:08
I did a bit of testing on this and it looks like a DNS server situation. Could be or it could be the authoritative name servers for your domain, and I don't have enough data to say which it is that goes awry. When I do a straight request to several times in a row I get different responses. Sometimes it's fine and returns everything, sometimes it doesn't give the A record and is NXDOMAIN. Either the zone file is messed up or one of these name servers are configured wrong. – Peter Oct 16 '12 at 21:34

Although this DNS configuration is terribly slow and error prone, there's no DNS to blame, and your record is working correctly.

Here's what happens. When you query about, this server is configured to answer for, but it does not have a record for and returns a default CNAME

This CNAME now is NOT in the zone of it belongs to zone So if you attempt to resolve it through, you'll get an error. Instead, this name must be resolved starting from scratch from the root, down through the .info authorities.

The other DNS services you mention will respond for the CNAME because they are not DNS servers, they are DNS resolvers, so they will perform the entire procedure for you and return only the result.

Use dig +trace or the Delegation Lab to figure out who's authoritative for those zones and who you are supposed to query instead:

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