Re: router firwalls?

From: CZ (CZ_at_no99spam.com)
Date: 04/08/04


Date: Thu, 08 Apr 2004 04:38:17 GMT


>> Nope. A router only does NAT (network address translation). Some people
classify NAT as a firewall, but it's not in my opinion. It's simply how a
router routes packets from external IP's (internet) to internal IP's (LAN).

Neo:

Router and NAT are two different concepts.
Router: does routing between two subnets via DA (destination address) and a
route table (OSI layer 3 only).
NAT as we use it: does one-to-many address translation via matching to a
port table (OSI layers 3 & 4).

And a stateless firewall: does packet filtering via packet header values
(OSI layers 3 & 4).

The problem is liberal usage of the word "router".

My Netgear RT314 "router" provides the functionality of all of the
following:
Router
NAT
Inbound and outbound stateless firewall rules on both interfaces

Note that I have used the RT314 with NAT disabled and it works as a basic
router, it allows communication between two subnets.