A PC with Linux makes a decent router. I built a router using Linux
(kernel version 2.0.30) on a 100 MHz Pentium using 3 plain old NE-2000
clone cards (we have a truckload of those), and it performs really
well. I have no experience using 100BASET[X] with Linux, but the load
average on our router never exceeds 0.1, even with the security
filtering we do, which includes reassembling all fragmented packets. The
filtering rules are similar to what you find on commercial router
products, you can filter on source and destination address/port. One
thing lacking is the ability to filter on protocol (GRE etc.), but for
TCP/UDP/ICMP everything works fine.
This is not a 'protocol aware bridge' but it may be what you're looking for.
>Date: Tue, 29 Jul 1997 11:30:38 -0400
>From: Jason Cook <jc321397 @
>Subject: Fast Port Blocker
>Is there software for either Linux or NT that can handle port blocking =
>at high speeds such as switched Fast Ethernet? I need to filter all =
>traffic out that is not destined for certain ports between two networks. =
> A dedicated router at these speeds would be two expensive. What I need =
>is a protocol aware bridge. Any help is appreciated.
>MIS Dayton Systems Group