How traceroute operates

Archived from groups: comp.dcom.lans.ethernet (More info?)

Lukasz wrote:
> Hello
>
> Might someone describe briefly how traceroute operates??
>
> Thanks for your advice.
>
> Regards,
> Lukasz
>
>
While I am not a complete expert on traceroute, I can tell you a couple
things. Windows operating systems use ICMP to perform the traceroute,
and UNIX/LINUX operating systems use UDP to perform traceroutes.
Basically packets are sent to the destination starting with a TTL on the
IP header set to 1. The first router decrements that TTL, and the
packet is discarded. Your host is returned a message from the first
router. The host then increments the TTL by 1, and the next-hop router
(beyond the first router) is discovered. This process continues until
the destination is reached.

While this might not be the best explanation, I am sure there are a
bunch of smarty pants engineers that know more about traceroute and can
explain it better.

If you really want to learn the nuts and bolts of how traceroute works,
download Ethereal (http://www.ethereal.com) and take a capture of your
host completing a traceroute to some common domain like www.google.com.

-mike

Archived from groups: comp.dcom.lans.ethernet (More info?)

Lukasz <lkondrad@poczta.onet.pl> wrote:
> Hello

> Might someone describe briefly how traceroute operates??

"man traceroute" should give all information you need ;
"http://www.freebsd.org/cgi/man.cgi?query=traceroute&apropos=0&sektion=0&manpath=FreeBSD+5.2.1-RELEASE+and+Ports&format=html"

> Thanks for your advice.

> Regards,
> Lukasz



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