modify iptables

[Michael Klinosky <mpk2 enter net>]

If this is off-topic, please respond to me directly.

I want to set up SSH to use another port (not the default 22). I know 
how to set up SSH's config files, and config my modem, but iptables 
(just on the server machine?) is thwarting my effort.

Using iptables -nL, I see the line I need to change - how do I do that?