DNS lookup failing

Question

I have a primary and secondary domain controller that we use as our DNS servers. Users are getting mixed results with accessing websites. Some work fine, others are giving an error:

Network Access Message: The website cannot be found
Explanation: An IP address for the website you requested could not be found. 
As a result, it was not possible to access the site. 

For example, mcmaster.com will not work. If I run nslookup from the primary DC:

C:\Users\Administrator>nslookup mcmaster.com
Server:  dc.mydomain.local
Address:  10.1.1.35

Non-authoritative answer:
Name:    mcmaster.com
Address:  209.64.25.230

All looks well, but when I run nslookup with www. prepended to the address:

C:\Users\Administrator>nslookup www.mcmaster.com
Server:  dc.mydomain.local
Address:  10.1.1.35

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to dc.mydomain.local timed-out

Running nslookup www.mcmaster.com from the DC gives a different error:

*** backupdc.mydomain.local can't find www.mcmaster.com: Server failed

I think that mcmaster.com resolves to www.mcmaster.com, which results in the user not being able to access the site. Any ideas how I can troubleshoot this?

Answer 1

I ran an nslookup from my system at work and got the following response:

Server:  WHATEVER
Address:  xxx.xxx.xxx.xxx

Non-authoritative answer:
Name:    mcmaster.com
Address:  209.64.25.230


Server:  whatever
Address:  xxx.xxx.xxx.xxx

Non-authoritative answer:
Name:    a1843.b.akamai.net
Addresses:  23.66.232.17
          23.66.232.26
Aliases:  www.mcmaster.com
          www.mcmaster.com.edgesuite.net

My initial thought was whoever owns DNS for Mcmaster simply didn't have www as a valid response. I know I forward requests to www.whateverdomainirun.com to whateverdomainirun.com, but, seeing different DNS for the two surprised me.

When I navigate to http://mcmaster.com I get forwarded to the www. When I run a tracert on mcmaster.com it fails with Destination net unreachable. It looks to me like this company has put their site in Akamai's hands and either that's recent so your local DNS servers haven't updated and you could try flushing the cache and doing it again, or, in some way you're blocking requests to Akamai for some reason on your firewall.

Best and quick guess for you and it may be wildly wrong :).