DSL / Hardware Setup

[Jim]

I finally took the plunge and have DSL from Qwest.  I do have some
questions about the best way to set everything up.  So I turn to the
most knowledgeable people in Phoenix - PLUG.

Here is my setup:

Windows XP box @ 192.168.100
Linux Mandrake 10 box @ 192.168.20
Linux Mandrake SNF firewall box @ 192.168.1.150

Skylink Net 1008 fast ethernet switch with UpLink and 1X - 8X ethernet
connections

My question is do I need to install a second NIC in the firewall box so
that one NIC is connected to the ActionTec DSL modem and the second is
connected to the switch?

I imagine I will have more questions once that one is answered.

TIA

Jim