Question : Problem: Search switch/router port Tool

Hello

Is there a tool that can tell on witch port a specified PC is connected??

What I searching for is: I have a IP address of the main switch and the IP address of a PC.  I search for a tool that can tell me for example: the PC is connected on port X of switch X and switch x is connected on port y of the main switch.

Does something like that exist??

Answer : Problem: Search switch/router port Tool

If you ping the PC from its local segment, you will be able to look at it's arp cache and see what the MAC is for the PC.  On a PC to look at your arp cache, type "arp -a" at a command prompt.  Once on your switch, if you are on a "set based" switch such as the 6509, you can do a "show cam" to see the mac table.  This will show ports and the mac addresses associated.  From one of your IOS based switches, you can type "show mac-address-table" to see the table.

You may have to do some hunting.  For example if the PCs in question plug into 1900s and 2900s which plug into the 6509, to find it you would go to the 6509 first, which will point to a port connecting to one of the other switches.  From there you can find the PC.  

Also, be aware that if nothing has been talking to the PC in a while, you may need to ping it from multiple different machines so that traffic has passed through all of the different switches before you can find it.  For example, if you pinged it from a machine that is on the same 1900 as it, and then you go to the 6509, you probably won't find the MAC in the 6509's table.

Hopefully that helps.