D-Link DGS-6600-48T Product Manual - Page 898

DGS-6604 m Default Command Mode Usage Guideline Examples traceroute -w: 5 seconds -i: 1 -m: 30 -p: 33434 -q: 3 -t: 0 -s: 40 bytes Management interface mode or User EXEC To interrupt traceroute after the command has been issued, press Ctrl-C. The traceroute command uses the TTL field in the IP header to cause routers and servers to generate specific return messages. traceroute starts by sending a UDP datagram to the destination host with the TTL field set to 1. If a router finds a TTL value of 1 or 0, it drops the datagram and sends back an ICMP timeexceeded message to the sender. The traceroute facility determines the address of the first hop by examining the source address field of the ICMP timeexceeded message. To identify the next hop, traceroute again sends a UDP packet but this time with a TTL value of 2. The first router decrements the TTL field by 1 and sends the datagram to the next router. The second router sees a TTL value of 1, discards the datagram, and returns the time-exceeded message to the source. This process continues until the TTL is incremented to a value large enough for the datagram to reach the destination host (or until the maximum TTL is reached). To determine when a datagram has reached its destination, traceroute sets the UDP destination port in the datagram to a very large value that the destination host is unlikely to be using. When a host receives a datagram with an unrecognized port number, it sends an ICMP port unreachable error to the source. This message indicates to the traceroute facility that it has reached the destination. Use the TOS option to see if different types of service cause routes to change. Note : The specified OPTIONS can be any combination of each parameters. However, the parameters must be specified in the alphabetical order and upper case options are ahead of lower case options (similar to the PING command). This example shows how to traceroute the host with IP address "172.50.71.123". Switch# traceroute 172.50.71.123 traceroute to 172.50.71.123 (172.50.71.123), 30 hops max, 40 byte packets 1 172.50.71.123 (172.50.71.123) 0.847 ms 0.344 ms 0.376 ms Switch# CLI Reference Guide 888