This is was i did (and have done everytime i played in the past)
1. Go to Firewall on router setting
2. add new user-defined APP
3. Port 6112~6112
4. Port(same as above )6112
5. TCP
6. Added it to the list, and pressed save.
7. Restarted comp.
I cant host. Or at least ive made 5+ games, 5 min each and noone joined.