Which ports for http?

the_activ@activ.dhs.org
Sun, 25 Jan 2004 11:24:28 -0000

I''m trying to make my shorewall only allow access to http.
So I made a default reject policy and rules to allow port 80 and 443
outgoing. Now I know http uses other ports but I have no clue which ports
I also need to open.
Sorry for my ignorance but please help me, I tried lot''s and got
nowhere.