mac address of login user

[Ed Hon]

How do I see the mac address of someone logged in?

[Rita C Workman]

Have you tried:

arp -a

/rcw

[Richard Darling]

arp -a will do the trick.

You will need to know their ip address. If you don't know their ip addresss; and they are telnetting in from a Windows-based machine; and you have access to that machine you can also run:

"winipcfg" from "Start", "run", and you will get their ip address and mac address.

Hope this helps...RD

[Patrick Wallek · Accepted solution]

To id the MAC address of a user that is logged in you can do the following:

who -R -- This lists all users logged in and displays the host they are logged in from if via the network. If they are logged in via a serial port or on the console then it displays the local machine name, I think.

arp -a | grep host_name -- Use the host name you got from the 'who -R' above. This will give you the MAC address of the machine they are logged in from.

[Alberto Tagliaferri]

You'll always get IP addres with "who -R" but you'll get the MAC address just if the client is the same network as your server. If both are the same networks (same netmasks) ok, but if there's a router (OSI level3) between server and client you can't get client's MACs.

[rick jones]

given the overhead of doing DNS lookups of IP addresses to map them to hostnames, i would suggest uisng arp -an instead of arp -a. there can be quite a few entries in a system's arp cache