 The various implementations of traceroute all rely on ICMP Time Exceeded (type 11) packets being sent to the source.On Linux, "tracepath" is a utility similar to traceroute, with the primary difference of not requiring superuser privileges.Cisco's implementation of traceroute also uses a sequence of UDP datagrams, each with incrementing TTL values, to an invalid port number at the remote host; by default, UDP port 33434 is used.