Logging mac address?

[bigdog829]

Is there anyway to log guests/members mac address? I run a forum and have had a few problems with banned people re-joining under different ip's possibly using surf anonymous or some type of ip changing software. Or is there a hack for the members list that will show ip's for the moderators only?
Any help would greatly appreciated, its just becoming increasingly difficult to monitor the troublemakers. I would just like to stop them before they have a chance!

[m0nde]

Is there anyway to log guests/members mac address? The nature of how networks are built means that you will only ever be able to find the MAC addresses of PC's connected to your local Ethernet segment.

The MAC address is used to identify hardware at the data link layer, whereas the Internet works on the layers above, the network and transport layers. If we could get the MAC address of any node on an inter-connected network, then what would be the point of IP addresses?

ARP only caches the MAC addresses of devices on the same segment, so the Internet would need to be one massive Ethernet network for this to work. So when you ping google.com, ARP will cache the IP of your local gateway and the rest is done through IP.

- Sid