Networking – Understanding the Three Columns in Traceroute Output

networking

What do the three columns in traceroute output mean?

The man page isn't helpful: http://www.ss64.com/bash/traceroute.html

This is better, but a little more verbose than I'm looking for.

As an example.

traceroute to library.airnews.net (206.66.12.202), 30 hops max, 40 byte packets
 1  rbrt3 (208.225.64.50)  4.867 ms  4.893 ms  3.449 ms
 2  519.Hssi2-0-0.GW1.EWR1.ALTER.NET (157.130.0.17)  6.918 ms  8.721 ms  16.476 ms
 3  113.ATM3-0.XR2.EWR1.ALTER.NET (146.188.176.38)  6.323 ms  6.123 ms  7.011 ms
 4  192.ATM2-0.TR2.EWR1.ALTER.NET (146.188.176.82)  6.955 ms  15.400 ms  6.684 ms
 5  105.ATM6-0.TR2.DFW4.ALTER.NET (146.188.136.245)  49.105 ms  49.921 ms  47.371 ms
 6  298.ATM7-0.XR2.DFW4.ALTER.NET (146.188.240.77)  48.162 ms  48.052 ms  47.565 ms
 7  194.ATM9-0-0.GW1.DFW1.ALTER.NET (146.188.240.45)  47.886 ms  47.380 ms  50.690 ms
 8  iadfw3-gw.customer.ALTER.NET (137.39.138.74)  69.827 ms  68.112 ms  66.859 ms
 9  library.airnews.net (206.66.12.202)  174.853 ms  163.945 ms  147.501 ms

Best Answer

Traceroute sends out three packets per TTL increment. Each column corresponds to the time is took to get one packet back (round-trip-time).

This tries to account for situations such as:

  • A traceroute packet is routed along a different link than other attempts

    11 130.117.3.201 (130.117.3.201) 109.762 ms 130.117.49.197 (130.117.49.197) 118.191 ms 107.262 ms

  • A traceroute packet is dropped

    9 154.54.26.142 (154.54.26.142) 104.153 ms * *

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