Traceroute

[zeitzytoun]

Hello,

I'm trying to find the list of switches that a packet passes through during the send and receive phases between source and destination hosts , and the method that I found is using traceroute command. The problem is that traceroute return the routers this packets passes through, not the switches that I'm asking for. So, is there any thing similar to traceroute but there output is list of switches ?

Note: the switches of type cisco sf300 and sg300

Thanks in advance.

[Georg Pauwen]

Hello,

Cisco used to have the layer 2 traceroute utility, not sure if that is still around. Check the link below for details:

https://www.cisco.com/c/en/us/td/docs/routers/7600/ios/12-2SXF/configuration/guide/swcg/l2trace.pdf

[Giuseppe Larosa]

Hello @zeitzytoun ,

there is a traceroute mac command on catalyst switches not yours that has a different usage it can provide the switch and access port where a specific MAC address is learned.

In general L3 traceroute is based on IPv4 header TTL field and there is no TTL field in an ethernet frame or also a VLAN tagged ethernet frame.

Switches behave like transparent bridges and are not allowed to modify the forwarded frames.

So you can use show ip arp and show mac address-table on CLI of switches to find where a MAC address is connected but there is no tool that provides the sequence of switches the frame is going through.

Be aware that   the topology is chosen by STP.

Hope to help

Giuseppe

[pieterh]

you need additional tools to automate this, like Cisco APIC-EM or Cisco DNA

they both provide a "path trace" tool that combines L2 and L3 information