An easy way to make Heroes Over Europe work behind your router is to setup your gaming PC in the DMZ. To learn about how to setup your gaming PC in the DMZ, check your router’s documentation.
If you don't want to set your gaming PC in the DMZ, then you'll have to do some special configuration to your router or firewall (open ports) to make sure all the game’s features work properly.
Here are the ports you'll have to open, or forward:
Please make sure that you have the latest firmware driver updates for your router from the manufacturers website.