Access machine on local network using external IP

Question

I'm using Netgear WNR2000 router on my network. I have setup a machine on my network to be a DMZ server. I've got an app running on that server on port 1178. From outside my network, I can telnet into that port fine... however, from inside the network I can't telnet to my external ip and get to it, even though I can from the internal IP.

Is there a way to setup a "route" (for lack of knowing another term) to use the same external ip to access the same service regardless of being inside or outside the network?

Answer 1

If you want to access a computer that is inside a NATted network from inside with the external IP, you need special rules. This is commonly referred as "NAT loopback".

From what I see here: "NETGEAR WNR2000 : With firmware 1.2.3.7 loopback now enabled 'out of the box'"

In your case you are in an even more complicated situation as you add a DMZ, but I feel it's the same problem.

Answer 2

I'm not familiar with the details of Netgear router OS, but what you want to do is check your firewall rules between your LAN and DMZ. Generally no access will be allowed between zones unless specifically specified, so you can add / modify this rule to allow access between these areas.

However on a larger note, if you only need a few ports to be exposed there's no reason to have the machine out in the DMZ. It's much safer to move the machine into the LAN and open the necessary firewall ports and create any necessary NAT rules.