Find a IP with the MAC address (reverse Lookup)


I've a MAC address... How I can find the IP Address of that machine.

Thank in advance.
Phil !
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scraig84Connect With a Mentor Commented:
Typically you would need to find it on one of your machine's arp tables.  If there is a router in your network, this is usually the most central place to gather that type of info.  On a cisco router, the command is "show arp" - it will give you a listing of the MAC addresses and their corresponding IP address.  On a windows box, from a DOS prompt you can type "arp -a" to see similar output.

Happy hunting - and good luck!
You also might look at your DHCP server.  It should list the MAC addresses of all machines that have leased IP addresses on the network.
Maybe it's only running IPX so doesn't have an IP address?
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Interesting thought - but I think you might want to refer back to the question...
I have read the question.

I was simply pointing out that the question "I've a MAC address... How I can find the IP Address of that machine." is invalid since it might be running properly with no IP addresses (or maybe 20 of them) bound to the same card/mac address. Am I wrong to do that?

You are right in your first comment that it is pot-luck that you see the arp entry on a machine or see it when sniffing the cable so you should get the points.  There's no guaranteed interrogation method short of a DoS attack against it and see which user complains. At least you can find the make of the card normally though.
If you know the subnet it is sitting on, ping the broadcast address from a windows machine. Then inspect the arp table afterwards.

If your subnet was with a subnet of

Then would run;


That might do it for you, good luck
samphiAuthor Commented:
Hi All,

I'm happy to see that you're interested in my question!

I'm checked my routers and switches, and I have a abnormal plug. (too much transfer) and I have only his MAC addresse...

There's not a DHCP... There's a static IP...
Yes "ARP -a" is a good utility, but I was not found that IP... Actually, I'm thinking that's a printer...

I will wait still before distributing the points...

My "hunting" continue...
Excuse my english.
Phil !

ps: If that continues, I'll unplug this cable and I'll receive a call ;o)
Go to and in the search bar put
"mac address" (without the quotes).  It will turn up some tools like Whaddayagot 2.0 and APK GetMacAddress 1.0 that will help you to find the info you're looking for.  There are other network monitoring tools that will show that information also.
andyalderConnect With a Mentor Commented:
If you think it's a printer then the first step is to find the manufacturer from something lookup chart like or
when you have an MAC address and want to find out who's MAC is that, you use reverse ARP (RARP)... it functions just like a ARP but instead of asking 'i got an ip x.y.z.n what is the MAC?', it asks 'i got an MAC what is the IP?' if the destination has one it would send...
<off topic>
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<on topic>
I thought RARP was a forerunner to BOOTP and DHCP, unless he has a RARP server to query your answer means that nowadays I would look it up on a DHCP server which Geoff suggested earlier. Correct me if there is a protocol to query the MAC address for it's possible IP addresses.
Sorry no offence but kakarika is wrong. RARP is used to by a diskless device to find its IP address using a BOOTP Server.
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Phil, you still with us? any correlation with that MAC address and a manufacturer or is it a deliberate attack with a cloned MAC address?

Surely to have seen the MAC address on the network is to posess a trace containing it in the header of a packet, so lets examine that trace or the output of the tool that saw it in the first place or did some comment lead you to identifying it and you ran away without acknowledging the hint that helped identify it.

I'd rather see this paq'd with 0 points for all than the knowledge wasted, "I'm happy to see that you're interested in my question!" damn right there, but now we are interested in the solution and you haven't commented for a while.
samphiAuthor Commented:
Hi andyalder and all,

I've somes seconds...;-)

Ok, My switch indicated 1Gig transfer in one night, And I've only the MAC address. Then I going to hunting to IP.

I received somes tools and tips :
"ARP -a" 

And with this links, I discovered that MAC is not a PC. there's a defect printer. I was gone searching for that printer, floor by floor...  I'm always interested to find a good tip or tool for trace the IP via the MAC.

Thank you for your help.
I continue...
I keep you informed...

Phil !
Just remembered, assuming it's a jetdirect you can do
"arp -s <ip address> <mac address>" where <ip address> is a spare IP address on your local subnet and <mac address> is the mac of the printer. Next "telnet <ip address>" and you get the menu of the jetdirect and can read what it's stored IP address is. Then delete the static arp entry and print a "help please phone IT and tell me where this printer is" message to it.

Doesn't work with a PC as the target since they don't respond to the packets unless the MAC and IP are both correct but printers normally respond whatever the IP address is if the MAC is theirs. It was the only way to initially setup jetdirects before jetadmin for unix was written. Method probably works with other printers as well.

Of course you could use wspingpro or similar mapping program to ping every address on the local subnet then look in arp cache but that won't help unless it has an address on that subnet.
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For what it's worth I had a similar issue (MAC but IP unknown).  Followed UKWizard's advice and voila IP matching the MAC.
If you have a linux machine on your network load up arpwatch.  It will watch the network and build a table (arp.dat) that you can refer to.

C:\>arp -a 00-12-D9-3C-50-22
ARP: bad argument: 00-12-D9-3C-50-22



itamt, this question was closed ages ago, you'll have to ask your own question on the syntax of the ARP command.

I can confirm however that that is not the correct syntax.
just use
arp -a
and it will list all mac adresses known to him.
CC Get Mac Address is a nice tool. One may try that as well..
First scan All IP addresses in your subne (

 then run "arp -a" in command line on your PC
If you had smart switches on the network, you could scan the switches with dumps of information on what ports are doing the most communication.
But, just like everyone else is saying, you need to see the traffic at it's source or close to it.

That being said, you could put a popular sniffer on the same switch and watch for the traffic, and narrow it down to the port, then, tone out the port with a popular tone generator of your choice.  $100 to $150 at the most for a good one.   Could be more if you are more interested in the really good ones.
I used the radmin ipscanner that adrimanssc recommended above and it worked well.  It gives you a nice list with client name, IP Address, and MAC Address and all 3 fields are sortable.
Tech SavyCommented:
if the machine is in the same subnet, well it could work or could not work if the device has contacted to the machine where u are running this command. Ur luck.
But this is what i usually do if that doesnt work, then the final step is to check the arp table of your router
go to a machine open command prompt
arp -a >1.txt & 1.txt

it will generate a text file and then press CTRL + F and type the MAC address , boom if its either there with an ip or its not there lol.

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