Description

This article provides explanations for the various annotations seen in traceroute output.

Symptoms

In the following example output, what does !<10> mean?

lab@router> traceroute routing-instance vrf 172.22.168.121 <snip>
3 172.22.168.121 (172.22.168.121) 0.560 ms !<10> 0.572 ms !<10> 0.535 ms !<10>

 

Solution

In the above example, ! <num> (ICMP unreachable code <num> ). So the ‘10’ in this case should be ‘unreachable code’ of ICMP which code means "Communication with Destination Host is Administratively Prohibited”.
It may also be due to the destination host having an ACL or firewall filter that is denying UDP traceroute packets.

Possible annotations after the time:

  • !H, got a host unreachable
  • !N, got a network unreachable
  • !P, got a protocol unreachable
  • !S, got a source route failed
  • !F, got a fragmentation needed
  • !X communication administratively prohibited
  • ! <num>  (ICMP unreachable code <num> )

Also, more details are provided in the traceroute man-page on any Unix system.

 

Former Article Id

18170

Modification History

Article ownership changed to Feng He who was the last one to update. Modifications to article suggested. Archive tag removed because the article is being used, as per author.
 

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