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From: tgsmith@sundc.East.Sun.COM (Tim Smith - Consultant Sun Baltimore)
Newsgroups: comp.dcom.lans
Subject: Re: Smart filtering within a protocol on bridge/router?
Summary: cisco can do it- proteon probably can't
Message-ID: <10810@sundc.East.Sun.COM>
Date: 16 Nov 89 15:19:13 GMT
References: <2598@aecom.yu.edu>
Sender: news@sundc.East.Sun.COM
Reply-To: tgsmith@sundc.East.Sun.COM (Tim Smith - Consultant Sun Baltimore)
Organization: Sun Microsystems, Vienna, VA
Lines: 46

In article <2598@aecom.yu.edu> glen@aecom.yu.edu (Glen M. Marianko) writes:
>Anyone ever hear of a bridge or router that can filter traffic within
>a protocol.  Like tell the box to "filter all TELNET traffic" or
>"allow only SMTP traffic" either globally or for individual nodes.
>Granted, this is rather esoteric - but security is the concept
>here.

cisco routers can do exactly what you want.  Their filtering is really
flexible and their boxes are real fast and real reliable.  They can
filter on source/destination IP net/addr, protocol, and TCP/UDP port
numbers.

I once had a host that was killing one of my vaxes with a mail loop.
The folks responsible for the offending machine were unable/unwilling
to fix things so I installed a filter in the cisco to ONLY block smtp
traffic from the offending host to the offended host.  The clowns on
the offending host were a bit confused before I told them what I had
done- "Well we can ping them, rlogin to them, telnet to them, but we
can't get mail to them.  What the hell is going on?"  Made my host
happy and also convinced them to fix their host.

Proteon's can do filtering on source net, dest net, and maybe a little
more.  Their filtering is not as sophisticated as cisco`s.

Contact info:

cisco systems
1360 Willow Road
Menlo Park, CA 94025
(800) 553-6387

Proteon
508-898-3100

NB:  Usual disclaimers apply.  I don't have any financial interest in
either company.  I have worked with both companies hardware.

        Tim Smith - Technical Consultant
US mail:Sun Microsystems        E-mail:
        6797 Dorsey Road                internet:tgsmith@sunbalt.east.sun.com
        Suite 4                         uucp    :sundc!timsmith
        Baltimore, MD 21227
MaBell :(301)379-5000

As goes without saying(but will be said anyway):  If I were speaking
for sun you would be paying to hear it.