IP to MAC resolution

admin_2 · ‎02-26-2009

I know the IP of a device on my multi-VLAN network. How do I find which switch and port it is connected to?

ohassairi · ‎02-26-2009

if you have a ciscoworks machine this could be easy.

i imagine you don't have it.

1-first determine the mac address of your computer .

2-then choose one switch that has PCs in same vlan, telnet to it and issue the command

switch# sho mac-address-table | inc yourmacaddress

if the PC is connected to that switch then you will get directly the port.

if not the switch will indicate to you an uplink to a second switch

repeat same steps with second switch

Report Inappropriate Content · ‎02-26-2009

The device I'm trying to find is a printer so I'm not able to telenet into it.

Tshi M · ‎02-26-2009

sh ip arp x.x.x.x.

this will return the MAC address belonging to the IP

once you have the mac address, you use

sh mac-add | i xxxx.xxxx.xxxx

below is an example

3560-sw1#sh ip arp 10.64.155.62

Protocol Address Age (min) Hardware Addr Type Interface

Internet 10.64.155.62 21 0011.43b4.7f0f ARPA Vlan101

3560-sw1#sh mac-add | i 0011.43b4.7f0f

101 0011.43b4.7f0f DYNAMIC Gi0/32

Report Inappropriate Content · ‎02-26-2009

I would already have to know which switch the printer is attached to in order for that to work - correct?

Tshi M · ‎02-26-2009

No you don't need to know the switch where the printer is connected to. You can use the sh ip arp x.x.x.x from any switch. Once the mac address is found, you can work your way up to where the device is connected. the sh mac-add | i xxxx.xxxx.xxxx might point to an uplink. You will then go to that switch and work your way to the right switch.

Report Inappropriate Content · ‎02-26-2009

Mohamad Qayoom · ‎02-26-2009

No, you can go to the core and do the following:

ping x.x.x.x

sh ip arp x.x.x.x

Now you will see MAC address aaaa.bbbb.cccc

sh mac-add add aaaa.bbbb.cccc

Here you will see port-channel or uplink port. Now see what switch is connected through that port-channel onr uplink.

Go to that switch and do

sh mac-add add aaaa.bbbb.cccc

Mohamad Qayoom · ‎02-26-2009

No, you can go to the core and do the following:

ping x.x.x.x

sh ip arp x.x.x.x

Now you will see MAC address aaaa.bbbb.cccc

sh mac-add add aaaa.bbbb.cccc

Here you will see port-channel or uplink port. Now see what switch is connected through that port-channel onr uplink.

Go to that switch and do

sh mac-add add aaaa.bbbb.cccc

Terryn Barbarich · ‎02-26-2009

You can also use, trace mac ip