Client Filtering MN700

Archived from groups: microsoft.public.broadbandnet.hardware (More info?)

Can anyone tell me which ports to block when setting up
client filtering on my MN700?
All I'm doing is limiting internet access on the PC that
the kids use in the basement to certain hours. (in addition
to the parental controls)

"In the Outbound Port(s) boxes, type the outbound port
numbers for the data that you want to control."

I'd like to keep all functionality to the PC except
internet access, but I don't know enough about ports to
determine which ones. Would port 80 suffice?

Thanks in advance.