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Date:      Wed, 28 Nov 2001 21:45:41 -0800
From:      "Crist J. Clark" <cristjc@earthlink.net>
To:        klik <klik@unstable.org>
Cc:        Danny <eyezonme@gmx.net>, freebsd-security@FreeBSD.ORG
Subject:   Re: Ipfw + bpf interaction
Message-ID:  <20011128214541.J3985@blossom.cjclark.org>
In-Reply-To: <Pine.LNX.4.33.0111281329250.23570-100000@ezri.unstable.org>; from klik@unstable.org on Wed, Nov 28, 2001 at 01:30:56PM -0500
References:  <000e01c17834$5cf1d670$020144c0@danny> <Pine.LNX.4.33.0111281329250.23570-100000@ezri.unstable.org>

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On Wed, Nov 28, 2001 at 01:30:56PM -0500, klik wrote:
> Put those deny statments before your divert rule

It shouldn't make a difference unless the incoming HTTP connections
are being redirected.

> On Wed, 28 Nov 2001, Danny wrote:
> 
> > Date: Wed, 28 Nov 2001 12:44:36 -0500
> > From: Danny <eyezonme@gmx.net>
> > To: freebsd-security@freebsd.org
> > Subject: Ipfw + bpf interaction
> >
> >
> > I've been experimenting with ipfw to horde off the hundreds of attempted
> > http requests per day (primarily all from @home customers) which I
> > suspect to be part of some lingering worm/ddos. My question is if a
> > connection attempt will still be recorded by clog(8) if the source IP is
> > blocked by ipfw?

There is nothing wrong. The bpf(4) device sees packets before they are
processed and blocked by ipfw(8).

[snip]

> > The rule seems to be added to ipfw's rule set, which for my box is as
> > follows:
> >
> > 	00050 1915738 1315695882 divert 8668 ip from any to any via ep1
> > 	00100    3360    1384342 allow ip from any to any via lo0
> > 	00200       0          0 deny ip from any to 127.0.0.0/8
> > 	00300       0          0 deny ip from 127.0.0.0/8 to any
> > 	00400    1596      65772 deny log logamount 500 ip from
> > another.bad.host to my.ip.address
> > 	00500       0          0 deny log logamount 500 ip from
> > 67.161.0.0/16 to my.ip.address
> > 	65535 3795144 2623014796 allow ip from any to any

However, if you are seeing these in the clog(8)s, you should also be
seeing them later blocked.
-- 
Crist J. Clark                     |     cjclark@alum.mit.edu
                                   |     cjclark@jhu.edu
http://people.freebsd.org/~cjc/    |     cjc@freebsd.org

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