Traceroute supporting ICMP ECHO

Mike Hogsett hogsett at csl.sri.com
Wed May 12 12:33:27 PDT 2004


> I'm using 4.7p1 here, and I've had all sorts of fun on occasion with
> traceroute and my various firewall/routers.  The default traceroute will
> not work since UDP traffic is apparently blocked on the return.  Opening up
> port ranges on my router just doesn't seem right.  However, Linux
> traceroute has a -I option (I think Windows tracert uses ICMP ECHO by
> default) which allows it to work through a home firewall router.  The
> FreeBSD port for mtr also works.
> 
> Is there anyone who has considered adding this capability to FreeBSD?

I think its already there. ( 4.9-RELEASE-p3 )

From traceoute(8)

       -P     Send  packets  of specified IP protocol. The currently supported
              protocols are: UDP, TCP, GRE and ICMP. Other protocols may  also
              be  specified  (either  by name or by number), though traceroute
              does not implement any special knowledge of  their  packet  for-
              mats. This option is useful for determining which router along a
              path may be blocking packets based on IP  protocol  number.  But
              see BUGS below.



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