*BSD News Article 78310


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From: tedm@agora.rdrop.com
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: 3c589c Promiscuous mode problems
Date: 14 Sep 1996 16:58:01 GMT
Organization: Symantec Corporation
Lines: 17
Message-ID: <51eo6p$t3q@symiserver2.symantec.com>
References: <3235E9DF.3456@browncow.com>
Reply-To: tedm@agora.rdrop.com
NNTP-Posting-Host: 198.6.34.1
X-Newsreader: IBM NewsReader/2 v1.2.5

In <3235E9DF.3456@browncow.com>, Bill Kish <kish@browncow.com> writes:
>Hi All,
>
> I am trying to get tcpdump working with my 3com 3c589c card, 
>tcpdump works fine for broadcast packets and those addressed to 
>the freebsd box, but I'm not picking up any other packets on the 
>network...

While I don't know what your looking to sniff, I feel compelled to point out that
all 3com cards block error packets _at the hardware layer_, thus while it is
possible to put them into promiscuous mode, it is unfortunately not very
useful to examine certain kinds of network problems.

Novell has done extensive research on this topic for their Lanalyzer product line
and has a text file in their FTP archives that lists hundreds of network cards
and whether they will pass error packets up to the driver layer.