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From: Marc <ccc@lebertbro.com>
To: netfilter@vger.kernel.org
Subject: Confusion about filtering traffic in a bridge scenario
Date: Wed, 11 Apr 2012 16:58:11 +0200	[thread overview]
Message-ID: <4F859C03.1080803@lebertbro.com> (raw)

Hello,

I was/am trying to setup packet filtering on a virtualisation host and
couldnt get it to work and was hoping for some pointers.

Heres the setup:

Said host has:
eth0 - the physical interface, no address assigned
br0 - the bridge interface, has IP 10.0.0.1 and gateway and default
route assigned to it
veth0 - the virtual interface for one of the VMs, has IP 192.168.0.1

both eth0 and veth0 are added to the bridge, the networking setup is
functional, however I seem to be unable to filter traffic to the VM with
iptables. Heres what Ive tried:

iptables -A FORWARD -m physdev --physdev-in eth0 --physdev-out veth0  -p
tcp --dport 22

However, this only results in a /var/log/messages entry:

kernel: physdev match: using --physdev-out in the OUTPUT, FORWARD and
POSTROUTING chains for non-bridged traffic is not supported anymore.

Since this _IS_ in fact bridged traffic, I dont see why I would get this
error?

Maybe Im looking at it the completely wrong way and physdev isnt even
the way to go here anymore, I dont know. Any kind of help is greatly
appreciated.

Oh, I figured I should add the following information:

Kernel is Linux 2.6.32-11, running Debian stable (6.0.4)

/etc/sysctl.conf contains these:

net.ipv4.ip_forward=1
net.ipv4.conf.all.rp_filter=1
net.ipv4.icmp_echo_ignore_broadcasts=1
net.ipv6.conf.all.proxy_ndp=1
net.bridge.bridge-nf-call-arptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1

iptables -I FORWARD -j REJECT -p tcp -i veth0 --dport 22
didnt stop ssh from working either

Regards, Marc






             reply	other threads:[~2012-04-11 14:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-11 14:58 Marc [this message]
2012-04-11 15:13 ` Confusion about filtering traffic in a bridge scenario Gáspár Lajos
2012-04-11 15:36 ` Olivier Nicole
2012-04-11 16:27   ` Marc
2012-04-13  6:06 ` hannah commodore
2012-04-13 12:55   ` Marc

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