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How to find the IP address of a user if you only have the mac address available?

How to find the IP address of a user if you only have the mac address available?

I need to find a IP address of a specific user and I only have the Mac address available, I'm using Ubuntu. Is this possible?

Asked by: Guest | Views: 90
Total answers/comments: 2
Guest [Entry]

"There no gaurantee that you will be able to do so, but you can try to use ARP to look up what addresses are known to the system you are on (on windows, the command is arp -g). But the arp cache expires and only systems that have ""talked"" to the system you are on will be displayed like this. Even then, if the machine is behind a router, you will only get the router IP address.

If you have access to the DHCP server, you may be able to look up the MAC address there and see what IP address it got. PROVIDED your network is using DHCP."
Guest [Entry]

"Try scanning your local network using nmap. If your target machine is connected, a simple grep for the relevant mac address should map it to the IP address.

[root@myhost ~]# nmap -nsP 192.168.0.0/24

Starting Nmap 4.20 ( http://insecuredotorg ) at 2009-09-08 09:25 BST
Host 192.168.0.1 appears to be up.
MAC Address: 00:aa:bb:bb:7D:21 (Hewlett-Packard Company)
Host 192.168.0.4 appears to be up.
MAC Address: 00:aa:bb:bb:B6:64 (Dell)
Host 192.168.0.12 appears to be up.
MAC Address: 00:aa:bb:bb:8F:2E (Micro-star International CO.)
Host 192.168.0.14 appears to be up.
MAC Address: 00:aa:bb:bb:9D:1B (Tyan Computer)
Host 192.168.0.19 appears to be up.
MAC Address: 00:aa:bb:bb:91:39 (Tyan Computer)

To be pedantic, you can then ping the host then check your arp table. Say you're looking for 00:aa:bb:bb:91:39 which is shown to have the IP 192.168.0.19

[root@myhost ~] ping 192.168.0.19
[root@myhost ~] arp -n | awk '/192.168.0.19/{print $1 "" - ""$3}'
192.168.0.19 00:aa:bb:bb:91:39"