SRE – Systems and Network
Tips and tricks
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Rysslog is allowing to send its logs from a file on a server to a remote server (or online service) that will collect and maintain all logs. Assumed server configuration We will here assume that you have a rsyslog server already…
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How to setup an IPSec tunnel with Strongswan with high-availability on Linux
It is possible to secure your communication between several sites (datacenters for example) by using an open-source VPN IPSec on your Linux System. We will see here how to: Set-up a VPN IPSec on Linux with Strongswan (https://www.strongswan.org) Set-up a…
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How to capture results of a watch in a file
For debugging purposes, it can sometimes be useful to write the results of a command executed at a given time lapse. You can easily monitor a command by using the watch command. By default a watch command is only displaying…
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Find which process is using a specific port
If you need to know/find which process is using a specific port on your system, you can use some default tools for troubleshooting: netstat lsof WARNING: For the use of these tools, you will need root rights (or sudo rights…
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Add a function in shell on Linux (make dmesg timestamps human readable)
You want to add a specific function on your shell which is not available in standard functions and you would like to be able to call it anywhere you want without the need to specify the script location? That’s quite…
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Create an interactive command-line menu using Python
It can be necessary to create a simple interactive menu on CLI (Command-Line Interface) using Python to allow users to make some choices while executing a script/program. As there is no standard library for this in Python, you will have…
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Create a repeating event on last day of each month on Google Calendar
There is no easy way to make an event repeating on last day of each month with Google Calendar. So here is a simple trick to pass through this and get an event repeating on the last day of each month.…
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Testing SMTP server using telnet (whether with authentication or not)
You can need to perform testing with your SMTP server and see if you are able to send mail with it. You have your domain name, and you want to check if mail server is answering properly? 1. Check the mail…
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Unsubscribe from birthdays calendar on Google Calendar
To unsubscribe from the Birthday’s calendar, here is the process: Click on the arrow in left panel besides Other calendars and choose Browser interesting calendards Go to the More tab On line Birthdays, click on Unsubscribe at the right of the ligne
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Testing an ISO or an USB bootable drive with QEMU
If you want to test an ISO image or a bootable USB drive you just prepared, you can do it very easily thanks to QEMU with a simple command-line. Obviously, you will need to install the QEMU package first so…