D-Link DGS-6600-48TS Configuration Guide - Page 599

Volume 12-Troubleshooting / Chapter 62-Testing Network Connectivity Tracing the Route to a Specific Destination In the following example, the user invokes the echo protocol to ping a host with the IPv6 address 2052:1::47:65:52:101: DGS-6600:2>enable DGS-6600:15#ping 2052:1::47:65:52:101 PING 2052:1::47:65:52:101(2052:1::47:65:52:101) 56(104) data bytes 64 bytes from 2052:1::47:65:52:101: icmp_seq=1 ttl=64 time=15.2 ms 64 bytes from 2052:1::47:65:52:101: icmp_seq=2 ttl=64 time=1.85 ms 64 bytes from 2052:1::47:65:52:101: icmp_seq=3 ttl=64 time=4.89 ms 64 bytes from 2052:1::47:65:52:101: icmp_seq=4 ttl=64 time=1.84 ms 64 bytes from 2052:1::47:65:52:101: icmp_seq=5 ttl=64 time=1.92 ms --- 2052:1::47:65:52:101 ping statistics --packets transmitted = 5, received = 5, packet loss = 0 (0%) round trip times min/avg/max/mdev = 1.840/5.143/15.200/5.163 ms DGS-6600:15# In the following example, the user invokes the echo protocol to ping a host with the IPv6 address fe80::215:e9ff:feb2:78e1. Since the IPv6 address is a link local address, the user is prompted to specify the output VLAN interface and specifies VLAN99: DGS-6600:2>enable DGS-6600:15#ping fe80::215:e9ff:feb2:78e1 Local-link address, Enter Output Interface: vlan99 PING fe80:215:e9ff:feb2:78e1(fe80::215:e9ff:feb2:78e1) from fe80::460:cff:fe10:98 vlan99: 56(104) data bytes 64 bytes from fe80::215:e9ff:feb2:78e1: icmp_seq=1 ttl=128 time=1.32 ms 64 bytes from fe80::215:e9ff:feb2:78e1: icmp_seq=1 ttl=128 time=0.916 ms 64 bytes from fe80::215:e9ff:feb2:78e1: icmp_seq=1 ttl=128 time=0.926 ms 64 bytes from fe80::215:e9ff:feb2:78e1: icmp_seq=1 ttl=128 time=0.951 ms 64 bytes from fe80::215:e9ff:feb2:78e1: icmp_seq=1 ttl=128 time=1.41 ms --- fe80::215:e9ff:feb2:78e1 ping statistics --packets transmitted = 5, received = 5, packet loss = 0 (0%) round trip times min/avg/max/mdev = 0.916/1.106/1.415/0.220 ms DGS-6600:15# Tracing the Route to a Specific Destination When the user has a problem accessing a specific destination, the user may need to check all the hops located on the routing path of the packet. The traceroute command is commonly used to find all the hops located on a routing path. The traceroute command uses the TTL field in the IP header to cause routers and servers to generate specific return messages. The traceroute utility initially sends 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, the datagram will be dropped and an ICMP "time-exceeded" message will be sent back to the sender. The traceroute utility determines the address of the first hop by examining the source address field of the ICMP time-exceeded message. To identify the next hop, the traceroute utility sends another 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). DGS-6600 Configuration Guide 599