Firewalls and GridGammon

Firewalls are an essential tool on the Internet, and are commonly used by companies to protect their users from attack. Similarly, home users often install firewalls on their Mac (Mac OS X has a built-in firewall, in the Sharing Sytem Preferences), or on other devices attached to their network.

If you are having problems connecting to GridGammon, it may be due to a firewall blocking your Mac's connection to the GridGammon servers. This page describes the network connections used by GridGammon to help you resolve firewall issues. It assumes some familiarity with TCP/IP addresses and port numbers. It does not provide information about how to configure your specific firewall settings, as that is beyond the scope of the GridGammon help.

GridGammon ports

The GridGammon Mac client logs into the backgammon servers by opening a connection to login.gridgammon.com, port 2502. This connection is used to verify your user name and password. Once that is complete, the server sends you a numeric IP address and port number to connect to the Lobby. The login connection terminates, and the client opens a new connection to the Lobby which remains active until you log off or quit GridGammon.

When you play or watch a match, another session is opened by the client to an IP address/port provided by the GridGammon servers. This gameplay session terminates when you leave the match.

The port numbers assigned by the server are dynamic, and are typically greater than 9999 (decimal).

No listening ports

The GridGammon client software on your Mac is always responsible for initiating TCP connections. The client does not open any ports for listening.

The GridGammon client software does not establish any direct IP connections with other users, all communication (gameplay, chatting) is between the client and server.