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Understanding the `traceroute` Command in Linux

The traceroute command is a diagnostic utility that displays the path a packet takes to reach a network host or device, showcasing the transit delays of packets across an Internet Protocol (IP) network. It's an invaluable tool for understanding network issues and the topology of a network path.

Basics of the traceroute Command

The principle behind traceroute is simple: it sends packets to a destination, then analyzes the responses to determine the hops taken to reach said destination.


traceroute [OPTIONS] destination

Using the traceroute Command and Combining Options

Default Use: Tracing the route to a domain:


This command provides a step-by-step breakdown of the entire path taken from the source machine to, noting any delays at each hop.

Using -I to Use ICMP ECHO for Probing:

traceroute -I

By default, traceroute uses UDP datagrams to elicit an ICMP response from intermediate gateways. The -I option makes traceroute use ICMP ECHO requests instead.

Sample traceroute Output

Here's an example output of a traceroute command:

traceroute to (, 30 hops max, 60 byte packets
1 ( 1.043 ms 1.021 ms 1.000 ms
2 ( 10.431 ms 10.415 ms 10.396 ms
3 ... (skipping several hops for brevity)
10 ( 24.052 ms 24.041 ms 24.023 ms

Reading the Output:

  • Each line represents a hop in the journey to the destination.

  • The IP address (and sometimes the domain name) of the hop is shown, followed by three round-trip time measurements (in milliseconds). These timings can help identify a bottleneck or problematic hop.

  • Sometimes, you might see * * *, indicating that the response was not received from that particular hop within the timeout period.

Key traceroute Options

--type-TUse TCP SYN for probes.
--icmp-IUse ICMP ECHO for probes.
--queries-qNumber of probes per ttl (default is 3).
--max-hops-mSet the max TTL value, which essentially limits the number of hops. The default is 30.
--port-pSet the destination port to use. It is either initial udp port value for default method or initial seq for icmp.
--help-hDisplay help message.


traceroute is a vital tool in understanding network paths and potential bottlenecks or issues in reaching a particular destination. However, note that some devices are configured not to respond to ICMP requests or might rate-limit such replies, leading to partial or misleading outputs. As always, understanding the tool and the context in which it operates is essential for correct interpretation.

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