Symptoms: Unable to connect with servers. Certain servers appear with IPv6 address (IE 2001:0db8:85a3:0000:0000:8a2e:0370:7334) instead of the standard IPv4 one (IE 192.0.2.235).
Cause: Freelancer was not designed to support IPv6. When IPv6 is activated and supported, the game might detect the IPv6 address first and attempt to use it, but it is not built to support it.
Solution(s): The dumbest solution is to use the reload button until the server is listed with an IPv4 address. This process however can be quite long winded.
Another method is to disable IPv6 altogether; the new protocol version is not very widespread yet, so disabling it is safe for now.
In order to do so, first go to your Control Panel (which can be found under My Computer or in the Start Menu usually). In Network Connections, you should see one or more adapters. One should be identified as being connected to a network. Double-click on it, then click on the Properties button. In the list of items, you should see "Internet Protocol version 6 (TCP/IPv6)"; untick the checkbox next to it and hit OK. It is best to reboot your computer after doing this.