I know about the whole port forwarding issues when hosting games, and I was having problems with that. I decided to just put myself in the DMZ and that has been fine port wise. I used port forward's port checker and every port seems to be open for me.
Even with this I am still having latency problems. If people are able to join my game, it frequently goes to the drop countdown and the player is dropped within the first minute or two.
My parents connection is fast, 9.6 down and 1.6 up on a speed test I did a second ago.
If it is any use, my usual latency on iCCup is around 630.
Any suggestions on the problem?