8.1 Introduction
The traceroute program is a handy debugging tool that allows us to further explore TCP/IP protocols.
8.2 Traceroute Program Operation
First, historically not all routers have supported the record route option, making it unusable on certain paths.
Second, record route is normally a one-way option
The third and major reason is that the room allocated for options in the IP header isn't large enough today to handle most routes.
8.3 LAN Output
We're now ready to run traceroute and see the output
8.4 WAN Output
The output shown earlier for our small internet is adequate for examining the protocols in action, but more a realistic use of traceroute involves larger internets such as the worldwide Internet
8.5 IP Source Routing Option
Traceroute Examples with Loose Source Routing
The -G option to traceroute lets us specify intermediate routers to be used with loose source routing
traceroute Examples with Strict Source Routing
The -G option in the author's version of traceroute is identical to the -g option described earlier, but the source route is strict instead of loose
Normally IP routing is dynamic with each router making a decision about which nexthop router to send the datagram to
