Port forwarding in Linux

[Jared Buck]

I need a little assistance here.

One of my friends tells me the reason Bittorrent is downloading so
slowly is because a certain group of ports isn't open.  I do not know
how to open ports in Linux.  I can tell you my computer is connected to
the Internet through a DSL router since everyone in my family uses DSL.

Could someone tell me how to open up the required ports?  I looked
through the archives and there's no record of a question of this type
being asked.

Jared