Command
Traceroute
Use
Allows you trace the path a router takes to get to a given destination. Traceroute is a good troubleshooting tool since it lets you verify optimal routing and routing loops.
Syntax
Router#traceroute <ip address or DNS name>
Example
In the below example, traceroute is used to see what path the router takes to get to google.com.
2611XM#traceroute google.com Translating “google.com”…domain server (10.10.2.1) [OK] Type escape sequence to abort. Tracing the route to google.com (74.125.45.100) 1 10.10.2.1 0 msec 4 msec 0 msec 2 * * * 3 rd1so-ge3-0-0-2.cg.shawcable.net (64.59.142.82) 28 msec 12 msec 13 msec 4 66.163.71.117 12 msec 16 msec 24 msec 5 rc2wh-pos0-15-5-0.vc.shawcable.net (66.163.76.186) 24 msec 49 msec 24 msec 6 rc1wt-pos1-0-0.wa.shawcable.net (66.163.76.2) 56 msec 28 msec 40 msec 7 74.125.48.233 24 msec 28 msec 32 msec 8 209.85.249.34 32 msec 156 msec 28 msec 9 66.249.95.210 32 msec 32 msec 209.85.249.16 36 msec 10 209.85.242.255 132 msec 92 msec 96 msec 11 209.85.254.243 88 msec 209.85.254.241 88 msec 209.85.254.243 96 msec 12 209.85.242.255 97 msec 209.85.253.145 96 msec 209.85.253.133 108 msec 13 google.com (74.125.45.100) 88 msec 88 msec 88 msec 2611XM#
Afterwards, traceroute is used to find a routing loop.
R1(config)#do trace 9.9.9.9 Type escape sequence to abort. Tracing the route to 9.9.9.9 1 10.1.1.2 36 msec 44 msec 24 msec 2 10.1.1.1 40 msec 40 msec 40 msec 3 * * *