1 (one) asterisk in traceroute

[supathsitaula]

Can someone explain if this is normal behavior?

There is always a asterisk on the last hop output when trace route to a destination is run.

R1#traceroute 10.0.0.1 source  172.0.0.2

Type escape sequence to abort.

Tracing the route to 10.0.0.1

VRF info: (vrf in name/id, vrf out name/id)

  1 10.2.0.122 44 msec 44 msec 48 msec

  2 10.1.0.109 44 msec 44 msec 48 msec

  3 10.0.0.110 44 msec *  44 msec

R1#traceroute 10.0.0.1 source  172.0.0.2

Type escape sequence to abort.

Tracing the route to 172.16.1.1

VRF info: (vrf in name/id, vrf out name/id)

  1 10.2.0.122 44 msec 44 msec 48 msec

  2 10.1.0.109 44 msec 44 msec 48 msec

  3 10.0.0.110 44 msec *  44 msec

[joseper2]

Hi,

The * will be always for the last hope, if the device is unreachable you will see the * as well.

http://www.cisco.com/c/en/us/support/docs/ip/ip-routed-protocols/22826-traceroute.html

Thanks!

[supathsitaula]

I don't think it's ALWAYS the case. Thank you for the link but it does not answer my question. I would like to know why it happens. Anyone?

[ciscomocsic]

This is due a Denial Of Service Mechanism on the routers.  The feature is called

ip icmp rate-limit unreachable and I think the command is self explanatory.  It will

limit outgoing icmp unreachable messages out interfaces. 

If that * is bugs you, go to the router you're tracing to and run:

no ip icmp rate-limit unreachable in global config mode.  Run the traceroute from the

source and see the results.  Now keep in mind this is a DoS prevention mechanism, be careful with this on production networks. Anyways now you know why that "bugging asterisk" appears on the last Hop.

Check this lnk:  http://routing-bits.com/2009/02/13/icmp-rate-limit/