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Accepted
thor
Asked: 2010-11-25 22:38:42 +0800 CST

Is it possible to use ebtables to filter traffic by MAC-addresses on simple ethernet interface, without bridging?

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I have a linux machine (my workstation). From there I can ping other local machines, let's say 192.168.1.22. Let's say I want to prohibit communication with 192.168.1.22 by it's MAC address. I'm trying a simple rule:

ebtables -I INPUT -s 00:24:1d:c9:0a:27 -j DROP

But still I can ping that host. Is ebtables limited to filtering traffic only on bridge interfaces?

firewall linux ethernet

2 Answers

  1. Best Answer

    Yes, ebtables only acts on frames traversing bridge interfaces. You can, however, do a nice layering violation and use the -m mac --mac-source iptables option.

    Whenever I'm doing anything at all complex with netfilter I keep this diagram close to hand: http://jengelh.medozas.de/images/nf-packet-flow.png

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  2. Thor, what you suggest is correct and is working. I justed tested it.

    You may need to update the routes by replacing bridged interfaces with the bridge interface itself, to make sure you're not bypassing the bridge.

    ip route del 192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.1
ip route add 192.168.1.0/24 dev br0  proto kernel  scope link  src 192.168.1.1
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