How do I make a server???

[KryptonicFox]

When I make a server on the game which I got from steam and my friend tries to join it doesn't let him something about port 6121

[dmantione]

Your internet router or modem is probably doing NAT. This means that your friend cannot connect to your PC, because your router/modem hides your PC from the internet.

You can do two things:
- Connect your PC directly to the internet. This will have security implications. So do so, your router/modem must be switched in a bridging mode.
- Configure a port forward. This is probably the best solution. You tell your router/modern to forward port 6121 to your PC. These devices usually have a web-interface to do this.