Getting IP address from Mac address?

[R.Mahendran_2]

Hi,

I have an ethernet H/W address of a server.
How can I find out the IP address of the same,
without loging into the server?

Will 'rarpc' help?

Thanks
R.Mahendran.

[Ravi_8]

Hi, Mahendran

#arp -a |grep

[Michael Tully]

Try this, but I'm sure the machine has to be on the same subnet.

# arp -a | grep

[R.Mahendran_2]

But arp database doesn't carry this address

[Ravi_8]

Hi,

As Michael says, machine has to be in same subnet, otherwise i haven't seen any method to find IP

[R.Mahendran_2]

Then,What does rarp do?

[Ravi_8]

look at man pages of rarp

[U.SivaKumar_2]

Hi,

Say you are in a windows 98 machine with IP address 90.0.0.1 and your server IP address is 90.0.0.50. Then to find out etherne H/W address.

c:\>ping 90.0.0.50

Then

c:\>arp -a | find "90.0.0.50"


IF you are in a windows machine in 100.0.0.0 network with IP address 100.0.0.1 and your network and server's network is connected by a router.

1) you will have to login to the router and execute the command.

Cisco router>ping 90.0.0.50
Cisco router>show arp | include 90.0.0.50

or

2)you will have to login in another unix server in 90.0.0.0 network. say 90.0.0.25

server2#ping 90.0.0.50
server2#arp -a | grep "90.0.0.50"

regards,
U.SivaKumar

[Yogeeraj_1]

Assuming at least that you know in which subnet (e.g. 10.0.1) the server lies.

Try this, but make sure that you are in the same subnet.

ping 10.0.1.0

You should get replies from all hosts!!

then go your arp -a|grep "hw address"

Again, some host may not respond to ping!

Quite difficult to find out in that case.

Hope this helps!

Best Regards
Yogeeraj

[Yogeeraj_1]

Assuming at least that you know in which subnet (e.g. 10.0.1) the server lies.

Try this, but make sure that you are in the same subnet.

ping 10.0.1.0

You should get replies from all hosts!!

then go your arp -a|grep "hw address"

Again, some host may not respond to ping!

Quite difficult to find out in that case.

Hope this helps!

Best Regards
Yogeeraj

[Ron Kinner]

Ask your router guy. His router keeps an ARP table which has a life of about four hours compared to the minutes you find on most hosts. If the thing has had any traffic from a local host in the last four hours the router will know about it and if not a ping to the subnet broadcast address may wake it up. (Note: the broadcast ping now ends in all ones (255 for a class C) and not 0's tho many devices still support 0's.)

A sniffer on the network will also find it fairly quickly if it ever does any talking.

A DHCP server if used on the network might know the ip address.

Another cruder way is to ask the switch what port the device is on and follow the cable back to desktop then do ipconfig, winipcfg or whatever is appropriate for the OS.

Ron