Solaris 7 software bundles the popular traceroute utility. The traceroute utility is used to trace the route an IP packet follows to an Internet host. Traceroute uses the IP protocol ttl (time to live) field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path, and PORT_UNREACHABLE (or ECHO_REPLY) from the destination host. The traceroute utility starts sending probes with a ttl of 1, and increases by one until it gets to the intended host or has passed through a maximum number of intermediate hosts.
The traceroute utility is especially useful for determining routing configuration problems and routing path failures. If a particular host is unreachable, the traceroute utility can be used to see what path the packet follows to the intended host and where possible failures occur. The traceroute utility also displays the round-trip time for each gateway along the path to the target host. This information can be useful for analyzing where traffic is slow between the two hosts.
For more information, see TCP/IP and Data Communications Administration Guide.