|I'm not sure how you have things setup but normal procedure to connect to a game server is the client enters the servers IP address.|
I suspect you dont' have static routable IP's and are using some sort of dynamic DNS to allow people to connect to you. If I'm right, you're probably also running this from home.
Some friends and I bought, and ran for some years, a server which had multiple FPS games running on it. It used to have 4 MOHAA games running and 2 COD4 games all at the same time. Clients connected using the IP address. Of course we had our physical server located at a colocation site and had a block of IP addresses and dedicated bandwidth to use.
If you're serious about this, I would look at getting some static IP's and a business class connection at the very least (assuming I'm right and you're running these servers from home). If you actually have a real server, or more than one, I would look at having it hosted at a colocation site that can provide you with dedicated bandwidth and a block of IP's.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.