Making Linux network bridge transparent for 802.1x packets
Update 17/01/2011: If you are interested in 802.1x bridging, have a look at my Tapping 802.1x Links with Marvin blog post.
802.1x authentication messages are sent in Ethernet frames with destination MAC address set to 01:80:C2:00:00:03. This address belongs to “IEEE 802.1D MAC Bridge Filtered MAC Group Addresses” (01:80:C2:00:00:00 to 01:80:C2:00:00:0F) and such frames are not supposed to be relayed by bridges conforming to IEEE 802.1D [2]. For a number of reasons, you may want these frames to go through your bridge.