External DNS Issue- Reverse DNS Not Resolving

[vdinenna]

Hi,

We are forwarding DNS requests for our sites and mail to our Internet facing DNS server. Our registrar is one company and the block of IPs are from ATT. The registrar has our our DNS server (NS1, SOA) and ATT DNS server (NS2), in this ordered. Our web pages and mail are coming in ok. However, some of our outgoing mail is delayed, possibly due to not having R-DNS configured correctly. External queries for PTR records fail. All others are ok.

In Windows 2003 Server, I have created PTR records manually. Also deleted the the A record(s) in the forward zone and recreated PTR with create file checked, but I get an error:

"The associated PTR record cannot be created, probably because the referenced reverse lookup zone cannot be found."

The reverse zone is there. ATT helped me config a few years ago, based on a block of IPs they provided.

Our firewall allows for DNS UDP and TCP 53 to the internet facing DNS server. I know it works because when checking records, our server was #2 and ATT was #1 it showed in the response of the test. I reversed the order and the test response showed the change. Only PTRs are not resolving.

My guess is that the A records (forward zone) and the PTR records (reverse zone) are out of sync some how.

Any ideas what I could do to fix this issue?

Thanks,

Vince

 

[Noway2]

Try using NSLOOKUP to query the DNS server in the forward and reverse directions, ie by name and by IP address. If it works in one but not the other, it is a good indication that there is a configuration problem.

 

[vdinenna]

Hi Noway2,

I ran NSLOOKUP internally and exterally from the web and the results are the same: Forward works fine, Reverse fails.

Not sure how to proceed. Was going to copy and save everything configured and erase it, then try to reconfigure it.

Any idea why Server 2003 won't let me create a PTR record?

Thanks,

Vince

 

[Noway2]

Take a look at this thread:

http://www.tek-tips.com/viewthread.cfm?qid=1559355.

I think it is relavent to your query.

There is probably a syntax error in the PTR file, and if memory serves, there is a restriction that entries need to begin in the first column (ie watch the whitespace).

The book DNS & BIND is a pretty good reference / introduction to the syntax of these resolver files, which you can probably dig for electronic copies containing enough of what you need.