How can I use traceroute to diagnose network problems?

Traceroute can show you the path that packets take from your computer to reach another computer. Here is an example of tracing a route from Sail's core network to google.com (parts of the output have been hidden for security reasons):

[~]$ traceroute google.com
traceroute to google.com (172.217.0.46), 30 hops max, 60 byte packets
 1  * * * 
 2  core-he2-rtr2.sailx.co (147.92.88.3)  4.724 ms  4.681 ms  4.656 ms
 3  ios-t0-0-0p99-br01-he2.sailx.co (147.92.88.195)  4.693 ms  4.664 ms  4.628 ms
 4  ve1879.core5.fmt2.he.net (65.19.141.137)  4.765 ms  4.943 ms  4.943 ms
 5  100ge16-1.core4.fmt2.he.net (184.105.81.25)  4.840 ms  4.813 ms 100ge14-1.core3.fmt2.he.net (184.105.65.177)  5.298 ms
 6  100ge14-2.core1.sjc2.he.net (72.52.92.246)  4.929 ms  3.977 ms  3.906 ms
 7  eqixsj-google-gige.google.com (206.223.116.21)  4.014 ms  1.503 ms  1.500 ms
 8  108.170.242.81 (108.170.242.81)  10.781 ms  10.304 ms  10.314 ms
 9  209.85.251.5 (209.85.251.5)  9.673 ms 209.85.251.9 (209.85.251.9)  9.845 ms 209.85.251.5 (209.85.251.5)  9.820 ms
10  lga15s43-in-f46.1e100.net (172.217.0.46)  11.113 ms  10.896 ms  10.858 ms

The traceroute output shows the routers or hosts that a packet follows from your computer to the destination address. The example output above shows that 10 "hops" are needed to reach the destination from this specific source. In the default setting of traceroute, three ping queries are sent to each host in the path, and the round-trip times are displayed as shown above. If a response is not received a star (*) is displayed instead of the time. 

Traceroute can be used to detect if the route that packets are taking from your computer to reach another computer is too long or contains a loop. 

In Windows machines, the command for traceroute is "tracert".