The most common reasons that servers are not visible are:
- Blocked by OS firewall
- Port forwarding not set up on router
- Network is behind carrier-grade NAT (CGNAT)
The Windows firewall should prompt you to allow access when you first launch your
game. If it no longer does this then verify in the firewall settings that the game
is allowed and not denied. For non-Windows operating systems please refer to your
documentation for instructions on how to allow specific ports through the firewall.
Review your router's documentation for instructions on how to set up port forwarding
to allow external traffic through to the game. FreeSpace 2 Open supports automatic
port forwarding if your router has NAT-PMP or Port Control Protocol (PCP) enabled.
This allows FreeSpace 2 Open to enable port forwarding only if, and only for as
long as, it's needed.
Unfortunately, if your internet provider uses carrier-grade NAT then it will not be
possible to host a server as you will be unable to set up port forwarding properly.
You can use the Active Servers List to help diagnose
your connectivity issues. If your server has a firewall issue it should indicate
that in the listing. If a firewall is not the problem then it's possible that there
is a version mismatch and the listing should indicate whether your server version
is older or newer than the recommended version.
If you are unable set up port forwarding then your best solution is to host your
game on an existing standalone server, or have a friend create the server instead.