DNS Resolution Puzzle

[cliweb]

Hello,

Can anybody please assist me with this puzzingly DNS resolution issue.

We have just migrated a number of TLD domains to new IP addresses.

All domains are hosted on a new single webserver. The DNS delegation is now complete.

Using Internet Explorer on an external PC we are able to resolve anyone of the migrated domain names. Using Internet Explorer on the Host webserver we are UNABLE to resolve any of the domain names.

Both the PC and the Host webserver share the same DNS settings (i.e)Under the TCP/IP setting both point to the same Primary and Secondary DNS IP addresses. Using Internet Explorer on the Host webserver server we ARE able to resolve allother domains (ie)

http://www.Google.com...

etc excluding our own domain names.

The only domains we cannot reslove is our own domain names which arehosted on this webserver? Any help would be greatly appreciated.

Thank you. Chris

 

[Cstorms]

So does the webserver also act as your dns server? After the migration do you have stale dns records that have old IP addresses? Have you cleared the cache on the client machines?

 

[Cstorms]

I spose I should say cleared cache via ipconfig /flushdns for anyone wondering what I meant.

 

[cliweb]

Hi Cstorms,

Thank you for your reply and assitance. It is much appreciated.

Our webserver does not act as a dns server. It hosts several websites only.

I have run ipconfig /flushdns and this has not resovled the issue.

It is most odd that only the domains hosted on this box cannot be reached? All other domains can be reached.

Thank you.

Chris

 

[Cstorms]

Are you using host headers or assigning an IP to each site in IIS? Have you checked (or even needed to) look at your A records to see if they are pointing to the correct address?

 

[cliweb]

Hi Cstorms,

We have now managed to resolve this puzzle.

Our webservers sits behind a F5 router and it was the way the 'virtual servers' were configured that caused this odd error.

Thank you again for your prompt assistance.

All the best Chris.