Since you plan to use pmfirewall, you're half way there.
There is no need for any additional hardware... the two NICs you have
connect the two computers, and a modem in one dials the ISP, correct?
This is enough.
When you install pmfirwall, your external interface will be ppp0 (your
modem) and
Hi have a home network setup, two computers each with a single NIC.
A crossover cable.
I can ping and telnet between them fine.
I want to share a dialup connection on one machine.
Can I use the single NIC with the same IP as the gateway, or do I define
another IP for the same card and call this t