Hi! I'm in a LAN and I'm interested if there are any log files for the MAC addresses on linux or how can I log them.

you want to know your MAC adresse?

su to root and do a ifconfig -a

it's the numbers after HWaddr:


If you want to know the MAC addr of other PC on your lan, you'll probably need a lan analyzer, like ethereal.

the iptables logs will usually show the mac addresses of hosts on your lan...

/sbin/arp -a
is that what you are looking for? Note that you will only see MAC addresses of systems on your local network, since MAC addresses aren't used across IP subnets. You also may not see many MAC addresses if you are on a switched port, since only broadcasts and traffic destined for your system will come through.

Logging MAC addresses is not very useful, it's more useful to attached MAC addresses to a switch port to stop muppets messing around with your cables.

MAC addresses are part of layer 2 and need to be translated via ARP to IP addresses.
If you have routed connections into your lan (which im sure you do) at layer 3 then MAC are not important as only the routers will use them.

MAC addresses are cached for 3 mins or so an ARP -a will only show you some of the recent address that your system wanted to resolve. i.e other broadcast systems etc... if you want to find each systems MAC address you'll need to do a ping sweep of the subnet then see the results from TCPdump or ethereal. the IP part of TCPIP will have to inculde it.

Kerberus