yes

Subject: yes
Name: ludicrous
Date: 3/19/2002 3:38:04 PM (GMT-7)
IP Address: 138.67.74.229
In Reply to: Re: My cable charges $6.96 per extra computer & posted by Castle50
Message:

the router uses the cable company-assigned IP and, from the outside, looks like a single machine just sitting there.

On the other side of the router, you can hook up four other computers (clear up to 50, even on the cheappie $80-100 router models, if you chain the uplink port to other switches or hubs) by using internal IP addresses. The router keeps track of which computer is actually after the incoming data via Network Address Translation, which also means it acts as a basic firewall.