What is ebtables?

[joseph]

The ebtables program is a filtering tool for a Linux-based bridging firewall. It enables transparent filtering of network traffic passing through a Linux bridge. The filtering possibilities are limited to link layer filtering and some basic filtering on higher network layers. Advanced logging, MAC DNAT/SNAT and brouter facilities are also included.

The ebtables tool can be combined with the other Linux filtering tools (iptables, ip6tables and arptables) to make a bridging firewall that is also capable of filtering these higher network layers. This is enabled through the bridge-netfilter architecture which is a part of the standard Linux kernel.

Project homepage: ebtables

[joseph]

An usage example is available here which is intended to prevent IP conflicts in Xen.
Preventing ip conflicts in xen | - [ t o i c . o r g ] -