"Relative issues" [problem with conection]

[JuanP]

Hi everyone.

My bro and me were playing factorio since the launch, and we are very happy with the results. Congratulations Factorio Staff!!

but... we have a problem:

When we want to play on multiplayer, i cant enter on his server, nevertheless, he can enter on my server. we have the same mods and everything to be balanced.

Who can explain me what is the problem?

Thanks.

Regards. JuanP.