What is ebtables?
The ebtables utility enables basic Ethernet frame filtering on a Linux bridge, logging, MAC NAT and brouting. It only provides basic IP filtering, the full-fledged IP filtering on a Linux bridge is done with iptables. The so-called bridge-nf code makes iptables see the bridged IP packets and enables transparent IP NAT. The firewalling tools iptables and ebtables can be used together and are complementary. ebtables tries to provide the bridge firewalling that iptables cannot provide, namely the filtering of non-IP traffic.