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Linux Tutorial Series

Linux Tutorial Series – 167 – The traceroute command

Here is the video version, if you prefer it:

The traceroute command is used to see the route of a packet sent from your computer to the destination computer. (Shotts, 2019)⁠ Remember, packets are just small chunks of data sent over the computer network.

An example of its usage:

mislav@mislavovo-racunalo:~$ traceroute www.google.com

traceroute to www.google.com (172.217.16.100), 30 hops max, 60 byte packets

1 speedport.ip (192.168.1.1) 4.490 ms 5.863 ms 7.275 ms

2 172.27.99.1 (172.27.99.1) 12.774 ms 15.713 ms 18.709 ms

3 172.28.238.67 (172.28.238.67) 21.826 ms 25.468 ms 26.822 ms

4 hdr11-gut21.ip.t-com.hr (195.29.224.145) 30.081 ms 33.572 ms hdr11-gut21-2.ip.t-com.hr (195.29.225.121) 35.273 ms

5 gtr11-hdr11.ip.t-com.hr (195.29.3.46) 37.511 ms 40.042 ms 42.717 ms

6 72.14.204.128 (72.14.204.128) 51.135 ms 13.224 ms 13.562 ms

7 74.125.242.241 (74.125.242.241) 17.242 ms 74.125.242.225 (74.125.242.225) 19.994 ms 22.164 ms

8 72.14.239.195 (72.14.239.195) 23.811 ms 27.805 ms 72.14.239.201 (72.14.239.201) 32.334 ms

9 bud02s25-in-f4.1e100.net (172.217.16.100) 32.541 ms 33.624 ms 35.218 ms

We can see all of the points that my packets visited until it finally reached www.google.com. If you were to see asterisks (*) instead of concrete information in any of the steps, that means that the router (the part of the networking hardware that routes the packets) is configured not to give away identifying information. Here this is not the case.

Thank you for reading!

References

Shotts, W. (2019). The Linux Command Line, Fifth Internet Edition. Retrieved from http://linuxcommand.org/tlcl.php. Pages 227-228

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Linux Tutorial Series

Linux Tutorial Series – 161.1 – A note on configuration files

I wanted to make a quick note to say that whenever you encounter an issue or want to configure something, use Google to find what file in particular you are editing. I mentioned some files I deem are sort of foundational to know (such as /etc/passwd), but I think that in 2020. it is reasonable to assume that you have access to the World Wide Web and that you can use Google to answer queries such as “How can I modify systemd startup services” or similar.

In the language of optimization, no need to over-optimize for the goal of knowing about Linux. Know just enough to be confident that you have the major pieces of the puzzle and know how they work, but if a particular detail pops up use Google to solve it.

Talk soon!