Switch name

[kakomaisa]

Hi all! 

I have around 100 switch and I have IP phones connected to those switches, Iam having the IP address and MAC address of the phone and I need to know which switch is that phone connected to it.

When i login to L3 switch and type show arp | include ip address it immediately find the mac address which I already have but the opposite is not correct.

How can i Find the switch from those two information's .

[M02@rt37]

Hello @kakomaisa,

On you L3 Switch do sh mac-address-table | include <ip.phone.MAC>

Example: 

• switch# show mac-address-table | include 0009.aabb.06e9

You will see from which interface the MAC is learned, then which Switch is connected to that interface.

Continue until you find the Switch where the IP Phone is connected. 

[Jon Marshall]

"sh mac address-table address <mac address>"  will show you which interface the mac has been learnt on which should be an uplink from one of your other switches.

Jon

[kakomaisa]

Hi Jon and M02 

That is the strange part, it does not show up there.

[Jon Marshall]

The arp cache timeout is a lot longer than the mac address table timeout. 

Can you ping the IP and check again ? 

Jon

[kakomaisa]

I ping the IP address and it is replying but when I do show mac address table | my mac address, it does not show up.

[Jon Marshall]

What is actual command you are entering ? 

Should just be able to do "sh mac address-table address <mac address>"  depending on switch version. 

Have to say I have had issues in past with mac addresses not showing in tables even though it does ping so it's not always obvious why it is not working. 

Jon

[kakomaisa]

I can do show mac address table and see a lot of mac addresses and for test I took one of the macs addresses I am seeing and do show | that mac address and it showed up. I tried 5 MAC addresses till now and no one showed up.

As I said the strange part is when you do show arp and then IP address it brings up the MAC address but when I did show arp and then mac address it return zero result.

[MHM Cisco World]

it CCNA basic MAC change when pass L3 interface 
so what you see I think is MAC of SVI (default Gateway)
so 
show mac check VLAN SVI in each SW

[kakomaisa]

In my case I have the mac address as well as IP address, so I am just testing the arp and it brings me the correct mac address.

[MHM Cisco World]

When i login to L3 switch and type show arp | include ip address it immediately find the mac address which I already have but the opposite is not correct. <<- what is incorrect 

[kakomaisa]

when I do sh arp | include mac address it does not bring up the ip address.

[MHM Cisco World]

sh arp | include hard <<- use hard instead of mac 

[MHM Cisco World]

[kakomaisa]

Hi MHM

same results, no luck.