Enabling Traceroute on Comware Switches

Unlike any other vendor I’ve worked on, comware switches and routers do not reply to traceroute attempts by default. If you traceroute through a router you’ll get no response on that hop:

C:\>tracert switch1
 Tracing route to switch1 [10.4.228.2]
 over a maximum of 30 hops:
 1    <1 ms    <1 ms    <1 ms  router2 [1.1.1.76]
   2     *        *        *     Request timed out.
   3     1 ms     1 ms     2 ms  switch1 [10.4.228.2]
 Trace complete.

The packets pass through the device as shown by a response from the next hop but there is no useful information about that comware device. The following commands (for v4 then v6) resolve this:

• ip unreachables enable
• ip ttl-expires enable
• ipv6 unreachables enable

This then provides the expected response with the device responding as expected:

 C:\>tracert switch1
 Tracing route to switch1 [10.4.228.2]
 over a maximum of 30 hops:
 1     1 ms    <1 ms    <1 ms   router2 [1.1.1.76] 
   2     1 ms     1 ms     3 ms  switch1 [10.4.228.2]
 Trace complete.