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Category: Networking

Traceroute alternative

Traceroute alternative

From time to time I work with machines with no traceroute installed and I need to debug networking. For those purposes, you can either install it using sudo apt-get install traceroute or use some alternatives.

Both should be available on Ubuntu 20.04 by default, but I am not sure if you can find them on older version or other distros. I will update this post with other linux distros and versions if I discover new tools or facts.

Connecting the Raspberry Pi Zero W/WH to WiFi

Connecting the Raspberry Pi Zero W/WH to WiFi

Recently I bought a Raspberry Pi Zero WH, and I wanted to connect it to my WiFi, but first 5 guides from Google were not working well, so I wanted to share the approach I used using raspi-config. 0. Get ready Raspbian on the Pi And connect to it using ethernet or plug in the monitor to it via HDMI. 1. Get ready SSH You can do this using sudo raspi-config (5. Interfacing options/P2 SSH) or using

Default credentials…

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Display apps and occupied ports (Linux)

Display apps and occupied ports (Linux)

PROBLEM: My app is not starting, because port is already in use! SOLUTION: Find it and kill it 🙂 netstat -tulpn Will provide nice table with all info you migh like, truncated outpus below:

sudo ss -tulpn More fresh, more detailed (i like it more than netstat)

Now you can find what is “eating” your ports and you are able to debug errors 🙂 Note: If you cannot see the PID, use sudo to execute the command

Test network bandwidth using iperf (Networking)

Test network bandwidth using iperf (Networking)

PROBLEM: I would like to determine network bandwidth between two devices. SOLUTION: Use very simple test tool – iperf! [?] What is bandwidth? https://searchnetworking.techtarget.com/definition/bandwidth First of all, download iperf from official website! It works on Windows, Linux, OS X or Android. I will use Windows on this case. Start cmd (as the admin, just to be sure) and navigate to iperf directory. If you do not know your IP address, just open new cmd and run ipconfig. If you want to run…

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Devil’s VLAN 666? (NETWORKING/CISCO)

Devil’s VLAN 666? (NETWORKING/CISCO)

PROBLEM: What the hell stands VLAN 666 for? SOLUTION: Native VLAN feature! [?] What is VLAN? https://study-ccna.com/what-is-a-vlan/ In most of the times, you can observe Vlan1 on your switch to be down / administratively down. And this is fine and correct, simply because of security reasons. Vlan1 is default Vlan so it cannot be deleted, but we can disable it and create another Vlan and force it to behave as the native one. By default, all ports are under Vlan 1, which…

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