Diagnosing Connectivity Issues
If you've set up a game server in AMP but are having issues connecting, there are a handful of things you should check.
What error are you getting?
When failing to connect, the two most common errors will be "Connection Refused", or "Connection Timed Out".
Connection Refused means that the other party explicitly refused the connection, and commonly means the application you're trying to connect to isn't running. It does however usually mean that your firewall rules are indeed set up correctly for that port.
Connection Timed Out means that the other party simply didn't answer the request. There's no way to know exactly why, as a party that deliberately declines to answer is indistinguishable from say a completely turned off system.
Is the server listening?
You can use the
netstat utility to see which ports are currently listening on your system.
netstat -an | find "LISTENING"
Ensure that the port you're expecting the game server to be using is shown by the netstat output. If it's not then it's not listening or has failed to start, and you should consult its log file for more information on why.
You can check what ports AMP is expecting an instance to be using by running
Most systems by default ship with their firewall configured to not allow incoming connections. If you're on a Home network, then a good test is to try connecting to the server from another computer on the same network.
If another computer on the same network cannot connect after you've verified that the server is listening, then the issue likely lies with the firewall rules on the server.
On Windows systems you should use the "Windows Defender Firewall with Advanced Security" control panel and add an exception for the specific port number. Don't add rules based on the executable.
For Linux you may need to consult your distributions documentation for the specific command required to allow a port. Generally speaking it'll be via either
iptables (root access required)
Port Forwarding (Home users only)
It is good practice to configure your network so that any computers running servers are given a static IP address. This means that any port forwarding rules you set up won't suddenly stop working if the servers internal IP address changes.
Some home ISPs also block certain ports. It's not uncommon for HTTP traffic over ports 80 and 8080 to be blocked, or to not be forwarded correctly if the routers web admin uses the same port.