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Date: Wed, 25 Jun 1997 08:46:54 -0500 (CDT)
From: Mark Tinguely <tinguely@plains.NoDak.edu>
Message-Id: <199706251346.IAA27447@plains.NoDak.edu>
To: questions@FreeBSD.ORG, sysadm@ns.sirena.ru
Subject: Re: ?/dev/bpf0
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>  When I going to use  'tcpdump' command I see this information:
>          tcpdump: /dev/bpf0: Devisce not configured.
>
>  How can I configure this devisce.

you need to add :

pseudo-device   bpfilter        4       #Berkeley packet filter

to your kernel configuration file and rebuild the kernel.

--mark.