
Originally Posted by
Mirage
You need to forward ports to each of your computers, and then set mIRC to use the ports forwarded to the computer mIRC is installed on.
To forward ports, consult your router's user manual (as I don't even know what kind of router you have). To make mIRC only use certain ports (those you've forwarded), go to "IRC Options -> Connect -> Options -> Advanced", then set the port range to the port range you forwarded to that particular computer.
If you can send from one PC but not the other, then the router is either configured to forward ports to one of your computers already, or the computer that can send is in fact set up to be the router, and has a direct Internet connection.