[NTLUG:Discuss] MS Windows vs. Linux Trace Route

[crem]

Greetings,

M$ sends icmp requests and expects icmp replys (default, only option).

mtr sends icmp requests and expects icmp replys (default, only option).

Depending on Linux distribution icmp request or udp are sent and expecting
icmp reply (default). Most linux distribution support -I for icmp request.
[Ubuntu 8.04 sent icmp but 8.10 sent icmp]

Unix sends udp and expects icmp replys (default). Solaris has always
supported the -I option.

When sending udp message ttl is incremented for each packet starting at
destination port 33434. The port number is incremented with each udp
message. Take a wild guess how IANA assigned port 33434. 

Note that when you do traceroute from Cisco routers/switches they will use
udp messages. If the oACL is configured to block udp in 33434+ range or iACL
block icmp reply, then the traceroute will not work. There is no icmp option
in traceroute for Cisco equipment. Cisco of course runs on a Linux variant. 

C. Rem
CCNA

------------
At the school that I am now teaching Linux at has a situation that I have
not seen before.

Using a M$ Windows system I am able to perform a tracert from the command
line in the lab.  When I use the Linux (Fedora 12) system, traceroute does
not work beyond the internal routers, but mtr does.  I typically do a
tracert to yahoo.com.

Anyone have thoughts on why?

Dennis
------------------------------