Firewall definition

From: Stuart Halliday (stuarth_at_ecs-tech.com)
Date: 12/24/03 

Date: 24 Dec 2003 14:17:20 -0800

Is a NAT Router technically a Firewall?

A lot of Router Manufacturers seem to list NAT as a Firewall feature
when selling ADSL/Cable Routers.

I say it's a byproduct of how NAT works rather than really a Firewall.

I say to be a Firewall means its must actively probe packets, block
suspicious ones and alert the user.

A colleague says just a Router with NAT is a Firewall.

Who's right? :-)