From: "Christian Benvenuti (benve)" <benve@cisco.com>
To: "Greg Scott" <GregScott@Infrasupport.com>, <netdev@vger.kernel.org>
Cc: "Graham Parenteau" <adfgrahame1@gmail.com>
Subject: RE: Very confused about broute DROP
Date: Thu, 15 Sep 2011 18:08:09 -0500 [thread overview]
Message-ID: <184D23435BECB444AB6B9D4630C8EC83028548FD@XMB-RCD-303.cisco.com> (raw)
In-Reply-To: <925A849792280C4E80C5461017A4B8A2A04438@mail733.InfraSupportEtc.com>
How about ARP? You need it too ...
> -----Original Message-----
> From: netdev-owner@vger.kernel.org [mailto:netdev-
> owner@vger.kernel.org] On Behalf Of Greg Scott
> Sent: Thursday, September 15, 2011 3:48 PM
> To: netdev@vger.kernel.org
> Cc: Graham Parenteau
> Subject: Very confused about broute DROP
>
> I don't get this. Why does:
>
> ebtables -t broute -A BROUTING -j DROP
>
> completely knock a Linux host offline?
>
> This is what the man page for ebtables says:
>
> The targets DROP and ACCEPT have a special meaning in the broute table
> (these names are used instead of more descriptive names to keep the
> implementation generic). DROP actually means the frame has to be
> routed, while ACCEPT means the frame has to be bridged. The BROUTING
> chain is traversed very early. However, it is only traversed by
> frames entering on a bridge port that is in forwarding state.
> Normally those frames would be bridged, but you can decide otherwise
> here. The redirect target is very handy here.
>
> So based on the above paragraph, I should be able to do something like
> this:
>
> # Here is what to bridge
> ebtables -t broute -A BROUTING -p IPv4 --ip-destination $PUBLIC_IP1 -j
> ACCEPT
> ebtables -t broute -A BROUTING -p IPv4 --ip-destination $PUBLIC_IP2 -j
> ACCEPT
>
> # Route everything else
> ebtables -t broute -A BROUTING -j DROP
>
> So I tried above and knocked that box completely offline. I'm missing
> something.
>
> Here is what the paragraph about redirect in the ebtables man pages
> says:
>
> The redirect target will change the MAC target address to that of the
> bridge device the frame arrived on. This target can only be used in
the
> BROUTING chain of the broute table and the PREROUTING chain of the
> nat
> table. In the BROUTING chain, the MAC address of the bridge port
> is
> used as destination address, in the PREROUTING chain, the MAC address
> of
> the bridge is used.
>
> OK - so this target MAC address - is this the MAC Address of an ethnn
> port that's part of the bridge, or the MAC Address of another node? I
> was thinking it was the MAC Address of another node, but maybe it's
> just
> the MAC Address of a port on this bridge?
>
> And there are some examples here:
> http://ebtables.sourceforge.net/examples/basic.html#ex_redirect
>
> that I really don't get. So instead of trial and error guessing, I
> figured I would ask.
>
> If anyone can help me understand this, I'll take a stab at writing it
> up
> as clearly as I know how for use in future versions of man pages.
>
> Thanks
>
> - Greg Scott
> --
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next prev parent reply other threads:[~2011-09-15 23:08 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-11 18:25 Bridging behavior apparently changed around the Fedora 14 time Greg Scott
2011-07-11 20:07 ` Stephen Hemminger
2011-07-11 20:41 ` Greg Scott
2011-07-11 20:49 ` Stephen Hemminger
2011-07-11 21:08 ` Greg Scott
2011-07-11 21:10 ` Stephen Hemminger
2011-07-11 21:16 ` Ben Greear
2011-07-12 3:06 ` Greg Scott
2011-07-11 21:16 ` Greg Scott
2011-07-11 21:24 ` Stephen Hemminger
2011-07-12 0:02 ` David Lamparter
2011-07-12 2:38 ` Greg Scott
2011-07-12 3:39 ` David Lamparter
2011-07-12 14:30 ` Greg Scott
2011-07-12 14:54 ` David Lamparter
2011-07-12 16:28 ` Greg Scott
2011-07-21 4:40 ` Greg Scott
2011-07-21 15:01 ` Greg Scott
[not found] ` <925A849792280C4E80C5461017A4B8A2A0413A@mail733.InfraSupportE tc.com>
2011-07-22 4:39 ` Greg Scott
2011-07-22 6:20 ` Greg Scott
2011-09-15 22:48 ` Very confused about broute DROP Greg Scott
2011-09-15 23:08 ` Christian Benvenuti (benve) [this message]
2011-09-16 3:19 ` Greg Scott
2011-09-16 4:23 ` Christian Benvenuti (benve)
2011-09-16 14:55 ` Greg Scott
2011-09-18 1:47 ` Greg Scott
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