Access hosted site from behind local network?

Question

I have a Windows server 2012 R2 machine running RRAS and DHCP. It has two ethernet interfaces: one for incoming internet traffic, and one for the local network.

This server also forwards various ports to the local LAN. One of them is for an HTTP server.

If I try to connect to the HTTP server from outside the local network, this works fine. If I try to do the same from the local network, however, it does not.

I have seen some suggestions as to how to solve this. One was changing the hosts file of the machines on the local area network. I am not interested in this solution. Another was to add a manual line to DNS on the server. I tried various things when it came to this, but with no luck. (I might not have done it in the correct manner.) The examples were to solve slightly different problems than the one I had, so I had to improvise, which might have led me to fail.

My question is, what possible ways are there, and if the simplest one is to configure the DNS on the server, could anyone tell me how to do this? Preferably in a very basic way.

Answer 1

I've been in this exact situation before (though not with RRAS). What you're looking for is called NAT Loopback. This can be complicated to setup, so an alternative is for clients to use the servers LAN IP address when on the same network. You can do this with the hosts file (as you mentioned) or an internal DNS server.

You can do this on your existing windows server by installing the DNS server role, then setting up forwarding (for external name resolution) and creating a zone for your domain with the appropriate records. This is called split-brain/split-horizon DNS, if you need to search for more info. Then you need to specify the DNS server in DHCP. If you're unsure what records to add to your local DNS zone, just copy all of them from your domains public DNS, and then change the necessary records pointing to your web server.