Cannot host or join many online multiplayer games

I've been having this issue where no guide I follow nor software I install can let me connect to other players.

Specifically, this happen in Terraria and Worms: Armageddon, but not Portal 2. I assume it has something to do with the fact that Terraria and Worms involve IP connections but on Portal both players connect to a company's server or something. I've tried setting up port-forwarding using a guide and giving myself a static IP address or something, but never really understood what was going on. In doing so people can consistently join my games in Terraria, but every other game still doesn't work and I still can't join games they host. I've tried Hamachi too and I can't join or host with that either. By now I've fiddled with so many options and tried so many things I don't know where to even start looking for what the issue may be, so I'm hoping someone on here might be able to help out.

Thanks in advance if you can.

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/512750/cannot-host-or-join-many-online-multiplayer-games/