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Does it possible to check which DNS server used for resolving domain name (in intraned network)? We have many steps: proxy, BigIP, domain controllers, etc. I have a complicated networks with many DNS server. Sometimes when in browser I use:

http://mysitedomainalias.mydomain.com

I receive web page, sometime after near 15 minutes I receive error about timeout. But when I use IP address instead of domain alias I always reach my web page. So I have decided that it could be a problem with DNS server. I would like to know common way how to resolve similar problems.

user710818
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  • Your question title and your question body seem to be out of sync: Your title asks ***why*** the DNS name isn't resolved while your question body asks ***where*** the name is expected to be resolved. – Filburt Jul 14 '14 at 12:37
  • thanks, you have help me to create better question – user710818 Jul 14 '14 at 12:46
  • I still have no idea what your question is. It's confusing at best. – deceze Jul 14 '14 at 12:54
  • Please explain what you don't understand. I will add all that you need. – user710818 Jul 14 '14 at 13:00
  • Please explain what exactly you *understand* about the process of DNS resolution, how you believe that process works. Then ask your question in the context of that explanation. It's unclear whether you're confused about how DNS resolution works, or whether you know exactly how it works and have a deeply technical detail question. It would help if you explain *why* you want to know this. – deceze Jul 14 '14 at 13:11

1 Answers1

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On *NIX systems, dig is a standard tool to test and debug DNS servers:

deceze$ dig google.com

...

;; QUESTION SECTION:
;google.com.            IN  A

;; ANSWER SECTION:
google.com.     5   IN  A   173.194.35.168
google.com.     5   IN  A   173.194.35.161
google.com.     5   IN  A   173.194.35.169
...

;; Query time: 84 msec
;; SERVER: 192.168.10.1#53(192.168.10.1)
;; WHEN: Mon Jul 14 15:59:05 2014
;; MSG SIZE  rcvd: 204

In the last part, SERVER signifies which DNS server answered our request.
Some more things you can then do with dig:

  • query a specific DNS server instead of the system's default:

    $ dig @mydns.example.com google.com

  • trace each step of the resolution chain to see any problems in the canonical name servers:

    $ dig google.com +trace

  • query specific record types:

    $ dig google.com NS
$ dig google.com MX
$ dig google.com ANY

See the manual: http://linux.die.net/man/1/dig

deceze
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