Plutonium

Xerxes How do I port forward? How come this wasn't necessary in the past 2 years?

I keep getting connection interrupted constantly in custom games with friends no matter who hosts. Whoever the host is is completely unaffected. I have 1 GB internet speed with screenshots to show. This problem has persisted in every single plutonium installation from WaW to BO2 with no reason or fix. Capping the max fps does nothing to solve the problem. All people except for the host have connection interrupted every 5 seconds and their ping shoots up dramatically. This only happens in custom games despite working perfectly in previous months. Need a proper fix to this issue and not a "ITS A SERVER ISSUE" crap.