Traceroute MAC address

[prashant dwivedi]

HI All,

I have doubt with traceroute mac address command, suppose i have FTP server connected to some switch and i am known to FTP server MAC address and IP address,can i trace to particular switch in which my Server connected..

Any help is greatly appreciated!!

Regards,

Prashant.

[b.julin]

The answer is "yes" so long as:

1) all switches between the switch where the "trace mac" command is run and the client are cisco.

2) all trunk ports between the two have CDP enabled

3) all switches can talk to the IP address advertised by its neighbor's CDP instance

3a) ...on UDP port 2228

The mac address tracing utility is a Cisco vendor specific feature. It sends a UDP packet to port 2228 of the advertised CDP peer address.  The packet is similar to CDP minus any checksums and the type fields are  1 byte.  It is fairly trivial to write a client such that mac tracing can be done by connected hosts that have established a CDP session with the switch, once you have a sample packet.