Date: Tue, 25 Jan 2005 11:14:46 -0800 From: Brooks Davis <brooks@one-eyed-alien.net> To: Rich Wales <richw@richw.org> Cc: freebsd-stable@freebsd.org Subject: Re: NIC acting promiscuously -- how to fix? Message-ID: <20050125191446.GA26504@odin.ac.hmc.edu> In-Reply-To: <20050125180025.S04220.richw@whodunit.richw.org> References: <20050125180025.S04220.richw@whodunit.richw.org>
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--mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 25, 2005 at 10:43:01AM -0800, Rich Wales wrote: > I'm running 5.3-RELEASE-p5 on a system that is functioning as a > NAT router/firewall using "pf". It works just fine, but . . . . >=20 > The external (Internet) network connection is giving me incoming > traffic addressed to other users all over my neighborhood (not > just the packets intended for me). The external NIC (an Accton > MPX 5030/5038, handled via the "rl" driver) appears to be running > promiscuously; it's accepting all these incoming packets, whether > addressed to me or not. >=20 > The flags shown for the NIC by the "ifconfig" command are: >=20 > rl0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 >=20 > Note that the PROMISC flag is =3Dnot=3D set, but the NIC seems to > be acting in a promiscuous fashion nevertheless. >=20 > Although my firewall (an old 800-MHz Athlon system) is able to > handle this extra load, I'd really like to configure it so that > the packets not intended for my site are silently dropped and > never seen by FreeBSD at all. (Aside from simple neatness, I'm > aware of the failings of the RealTek 8129/8139 and am hoping to > reduce overhead by filtering out the extraneous traffic before > the driver would see it.) >=20 > Any suggestions as to what I should do? Or is what I'm asking > simply impossible (and if so, why)? Thanks for any help. Without a dump of the traffic I can't really say what you're seeing, but on a broadcast network like Ethernet of any size containing windows machines, half a dozen packets per second of broadcast noise is pretty normal. Are the packets addressed to your MAC address, but to another non-broadcast IP? I can conceive of configurations bugs in emulated broadcast domains that could cause that. If so it's an interesting bug in your ISPs config. If not, you may have found a bug in your NICs driver or it's chipset/firmware. -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --mP3DRpeJDSE+ciuQ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFB9pqiXY6L6fI4GtQRAmnhAKCAM7YhA7bZqsnP7VdfNXSXHIswxACfdjud gBFB7KKVH19HnmsAuIg8r4A= =gasC -----END PGP SIGNATURE----- --mP3DRpeJDSE+ciuQ--
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