DNS requests from Solaris 10 box to Bind/MySQL DNS server fail

Question

We have some servers running solaris 9 and some running solaris 10. We also have a DNS server setup running BIND with the MySQL backend. When I query the DNS server from our solaris 9 boxes, they always work just fine. However, when I query the DNS server from our solaris 10 boxes, they always fail. Queries to other DNS servers from the Solaris 10 boxes work just fine - they only fail when being sent to this particular DNS server. Here's exactly what I'm doing:
ON SOLARIS 9 BOX:
bash-3.00$ nslookup google.com calo-sunset
Server: calo-sunset
Address: <IP_OF_DNS_SERVER>#53
Non-authoritative answer:
Name: google.com
Address: 64.233.187.99
Name: google.com
Address: 72.14.207.99
Name: google.com
Address: 209.85.171.99
ON SOLARIS 10 BOX:
bash-2.05$ nslookup google.com calo-sunset
*** Can't find server name for address <IP_OF_DNS_SERVER>: Non-existent host/domain
*** Default servers are not available
In the case of the SOLARIS 10 box, <IP_OF_DNS_SERVER> is correct - it knows the IP address of the DNS server, but apparently it doesn't recognize that it's actually a DNS server.
I am utterly perplexed by this. It seems to me that a DNS request is a DNS request, regardless of your OS. Clearly something is different from Solaris 9 to Solaris 10 though because the requests fail on all of our solaris 10 boxes, and they succeed on all of our Solaris 9 boxes. Incidentally, dig requests from the Solaris 10 box also fail, where they succeed on the Solaris 9 boxes.
I don't really know what other information I could offer that might be useful. If you have any information at all about this or ideas on what I might try to troubleshoot/fix it, I'd love to hear it. Thanks in advance.

Answer 1

First off, I am an idiot. I got this entire post backwards. The fact is that the DNS requests work swimmingly well on our Solaris 10 boxes. They fail on our Solaris 9 boxes. I don't know how I managed to read this post all of these times and not notice that I got that backwards. Nice.
In any case, I've found the problem. It was non-trivial to me because I am not terribly familiar with the inner-workings of DNS. To those who are, it may seem painfully obvious. To me it certainly was not.
The problem was that the DNS server (BIND 9 with MySQL backend) did not contain a reverse DNS entry for itself. Apparently this is a big problem for Solaris 9. I got a hint that this might be the cause when I turned on verbose debugging info when I ran nslookup (nslookup -d2). I had to add the PTR record for the DNS server itself. I don't know why Solaris 9 would require that a DNS server contain reverse DNS information about itself, but sure enough it does. As soon as I added that info, the Solaris 9 boxes were able to successfully query the DNS server. Very odd.
Anyway, I doubt anyone else will come across this problem, but if you do, now you know something that might fix it.
Edited by: dprater on Oct 7, 2008 8:09 PM