Can't Connect To Server On Local Network

[naizarak 4]

I'm running

a laptop with arma 3 configured to run as server

and a desktop running the arma 3 game, connecting to this server

with both devices running on the same home network

I have the laptop running steam in offline mode, with my profile online on the desktop. I can see my server in the server browser, but ping registers as 2500, and I can never connect - always get the "Connecting failed" error. Both computers can ping each other successfully over the network, and I have all proper ports forwarded. Interestingly if I run the arma server and client simultaneously on the desktop PC, I can see the server with a ping of 2500, but I can connect without problems. Does anybody have any ideas as to what's causing this? Thanks.

Update: I tried hosting the game from within Arma 3 on the laptop, but I still received the "Connecting failed" error on my desktop. Hosting the game on LAN didn't work either as my desktop couldn't find the game. Additionally I've tried connecting the laptop through ethernet and wifi but neither worked. All these issues have me thinking there's a problem with the router config?

Edited March 12, 2013 by naizarak

[Lokyi 10]

...are both computers logging in to the same Steam account?

Also, the laptop should be trying to connect locally, not to the external IP address, as your port forwarding should be going to your server, which means it won't send return packets to your laptop.