The server is one of the most important parts of a network, but you might encounter a variety of issues trying to set one up, or when your clients try to connect. Here's a few troubleshooting tips to make sure your server performs how it should.

Correct IP
Make sure you've set your client program to connect to the right IP address, that of your server. "127.0.0.1" is your local address, so while that might work for local testing, it won't work across the internet. LAN games will also require the hosts external IP. To find your IP, go to http://www.whatismyip.com and copy the address shown. It is more difficult to host a server which has a dynamic IP address, but it is possible using online services.

Port Forward
If your connection is behind a router, you should forward the game ports. You need to configure the router to allow incoming connections and data on your MMORPG's active ports. Visit http://www.portforward.com for assistance on how to port forward with your router.

Firewall Exceptions
Running a firewall and capable anti-virus is extremely important when hosting a server, but your firewall will likely try to block incoming connections from most sources. It is safe to add an exception, in this case for your game port. To do this, open your firewall options, and add an exception for whatever ports your game is using. This will allow your clients to connect to the server.