DNS Trickery

[Stuart_C]

We have just changed our E-mail address names and they are now different to the PC Domain names. When accessing our internal mail server it was fine because I could by pass the proxy, local DNS would then give it the local IP and away I went. Now it has to pick up the DNS from the internet, then go through the proxy bounce the traffic off the firewall (as it's got the external IP address) and it's just generally slowing up access to a local resource.

 

Bearing in mind i have a fully functioning DNS setup for our original domain (DomainA) is there a way to add in information so that for our New domain (DomainB) with the local IP address? I realise that it's going to cause issues accessing anything under domainB and require some manual maintenance but as there are only 3 or 4 external IP's manually maintaining thise is not a horrible task?

 

Basically, when on my local domain I'd like it to work out that webmail.domainB = local IP even though my existing DNS/Domain is DomainA

[ChrisMiles]

The normal way to do this is to create a primary DNS zone on your domain DNS for your external domain name and add A records with the internal IP address.

[DT2]

+1 for split dns ^ this prevents recursive lookups to resolve internal ips.

 

DT

[Stuart_C]

So just as simple as "new, Primary zone"? Store in AD or not bother (it's only going to have 4 records)

[twin--turbo]

+1 for split dns ^ this prevents recursive lookups to resolve internal ips.

 

DT

 

 

Yep Forward zone on your internal DNS with local IP's

 

Rob

[psydii]

Create a forward lookup zone for your public domain name. Add the CNAME/ALIAS entries you need using the IPs you want them to resolve to (which for some services may still be external). Works like a charm.

 

Just remember to keep both external and internal up to date as changes occur!

Edited January 16, 2013 by psydii
written at work, posted at home, others posted in the interim. D'oh.