Question about name resolution.

Anand Buddhdev anandb at ripe.net
Mon Oct 26 14:33:40 UTC 2015


On 26/10/15 13:50, Bhangui, Sandeep - BLS CTR wrote:

Hi Sandeep,

> At this point I am not clear whether this is an issue with our
> Internal Network or something beyond our control.

First question: have you looked at the BIND logs on your internal resolvers?

> A. The following link works fine from our Internal Network. If I do
> a dig on "www.adobe.com" I see an A record.
> 
> http://www.adobe.com/devnet/air/air-sdk-download.html

www.adobe.com is a CNAME to www.wip4.adobe.com, which has an A record.

> B. The following link does NOT work from our Internal Network. If I
> do
> a dig on "airdownload.adobe.com" I only see an CNAME record. And folks
> get the error host not resolvable when they try to access on our
> Internal Network.
> 
> http://airdownload.adobe.com

This leads to a 3-name CNAME chain into Akamai domains. Most resolvers
should be able to follow it. Perhaps yours isn't? Or your firewalls have
decided they know better?

> Not sure what exactly is happening here. Could this be an Firewall
> issue?
> 
> Any help or pointers would be appreciated. Not sure whether I have
> provided enough information.

Maybe, but you're best of looking at your caching resolver logs, and/or
firewalls logs.

Regards,
Anand


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