Traceroute and ICMP

[cisco_lite]

Would traceroute work if ICMP is blocked on the way to the destination.

[Harold Ritter]

This will not work if the traceroute command is issued from a MS platform, as it uses icmp request message as probe packets. Unix based hosts and Cisco routers on the other hand use UDP probe packets, so it should work in this case.

Regards

[Jon Marshall]

The answer is it depends.

Some OS's use ICMP for traceroute so yes if you blocked all ICMP you would block traceroute as well. Other OS's use UDP. See this doc for more details -

http://www.cisco.com/en/US/tech/tk364/technologies_tech_note09186a00801ae32a.shtml

Jon