DNS resolution Windows Internal DNS/External DNS

I said "ISP" I meant "public".

Ensure that the computers on the inside are all using the internal Windows DNS server.
Then create an A record for the site domain.com.  The A record should be webmail and point to 40.30.01.22.

Since DNS works by first going to what it can resolve locally, and then going out, this should take care of your issue.  Again, ensure that your primary DNS on the clients internally is pointing to your Windows DNS server, then create the necessary A record for the appropriate site, flush DNS on the clients, and all should be well.

dgj1menez:

I though about that when I first posted the question. The problem is that the internal DNS is "domain.local" but the external domain for the webmail host is "domain.com" so the FQDN for the host should be webmail.domain.com.
If I create an A record on my internal DNS the hostname will be webmail.domain.local. Any A record will be always "nameofthehost.domain.local".
 
Maybe I am missing something...please let me know if your idea was different.

IT-Monkey-Dave:

I think am not really understanding your anwser. My public DNS is running on the DMZ on a BIND server. The internal is a windows server. The public resolves queries for domain.com and the internal queries at domain.internal.

The public DNS resolves the host webmail.domain.com on two different IP's like I said before, and for outside resolution I want this to happen. What I would like to do is to have all my internal clients (internal DNS resolution) to resolve webmail.domain.com with one of the IP's.

Hi, llavara

What you will need to do is create a new forward lookup zone for domain.com, but only in your internal DNS on your Windows server.
1. Right mouse click forward lookup zones > create new zone
2. Choose primary zone (it's OK to leave the check box for it to be stored in AD)
3. Zone replication is to your tastes.  If you only have one internal DC server, leave it at default - it shouldn't matter.  If you only have DC servers that host internal DNS exclusively, leave it at default -it shouldn't matter.
4. Zone name: domain.com
5. For dynamic update, chose the best option that reflects your current security policy.
6. Create a new A record for domain.com, name it webmail and point it to 40.30.01.22
7. Flush DNS on the workstations, and test.  They should now all resolve webmail.domain.com to 40.30.01.22 only.  Externally, nothing changes, so that will go to your two IP addresses.
8. Also test anything else for domain.com and ensure they all work as intended internally.

Let us know how it goes.

Thanks. I could do that, the issue may be that the domain.com zone is hosted outside on the ISP external DNS. They also provide service for a website called domain.com.

If I create a zone called domain.com in my internal DNS and add then host I think I will conflict with the external "domain.com" zone that is being hosted outside. This will cause conflicts when resolving domain.com (like for example the external webiste, etc...)

My guess is that I could create a secondary zone that points to the external DNS and have the secondary sync with the external one, an then create the record for the webmail.domain.com.

I am not sure if that make any sense?

Any ideas?
 

You can have an internal DNS zone domain.com that has nothing to do with your "public" domain.com.  It's called split DNS.  I'm doing it here, works fine.  Having the internal zone won't affect external users at all.  But you will be able to control what your internal users resolve.  If you create the internal zone and there's only a single A record in the internal zone for webmail.domain.com at 40.30.01.22, then that's the only IP your internal users will access, which is what you want.  That is of course as long as your internal users are using the internal DNS server and not pointing to external DNS servers.  If there are any other public servers in domain.com that your internal users need DNS for, create A records for those as well.  There may be some overlap in the sense that you could have an A record defined in the external BIND server for www.domain.com as well as the same A record for www.domain.com on the internal server.  Won't conflict.

Thanks for the reply.

But here is my concern, my users connect to a website that is called www.domain.com (hosted outside) if I create an internal DNS zone in my WIndows DNS servers with the name of "domain.com" to store the "webmal.domain.com" at 40.30.01.22, then when they try to connect from the inside to the "www.domain.com" they are going to the IP of the server that is hosting the zone which is the Windows internal DNS (with the wrong IP for the site) and not the one at the external with the IP of the website "domain.com".

The external site is called like the domain so "domain.com" and has an IP 1.1.1.1 if I create an internal zone called "domain.com" the users will be redirected to 2.2.2.2 (Internal DNS) I don't know how to create a record for the "domain.com" itself to point to 1.1.1.1. Perhaps I am missing something?

I don't know if I was able to explain myself.  

Thanks again!  




 

In addition to the A record for webmail.domain,com, you would also create an A record in your internal DNS for www.domain.com that points to the external IP address of the web site.  That's what I've done for our internal domain.  Likewise, add A records for any other external IPs in domain.com that your users might access.

There is one slight complication: You may have your external DNS set up so that if a public user browses to http://domain.com (without specifying the www) it sends them to http://www.domain.com.  That won't work on the internal DNS zone for domain.com because domain.com has a different meaning internally (for Active Directory).  I don't know of any way around that.  As long as your users include the www in the url, they'll be fine though.

Hope that helps.  Or maybe I'm the one who's not understanding.  Sorry if that's the case.

IT-Monkey-Dave, thanks again for your help.

I though about creating an A record for the public site "domain.com" and then adding the external IP in my internal DNS, however the issue is that the zone in the internal DNS zone will be named "domain.com" and the website is accessible as "domain.com" so I don't know how the A record take place here?
I don't have a hostname for the public website, is simply www.domain.com and then the public IP (ISP) so i am not sure how to create an A record within the internal DNS to point to the external site that is called like my internal DNS zone.
I hope I was able to explain myself...
Thanks for the help!