(Note: This page is updated every now and then, according to new Python releases and other interesting details. Last updated: 2025-08-10) Even though I’ve used Python programming language on-and-off since about year 2000, I only started paying more attention to specific Python versions around 2016 when I gradually started using Python more seriously in devops. […]
A long time ago I discovered screen. It made it possible to start applications in Linux and then disconnecting the SSH session, without stopping the applications. It was magic: otherwise the the applications just terminated if the SSH connection was lost. Then I heard about tmux. It was like screen on steroids! I could split […]
Short one: How to make a serial console server (or terminal server) with a Raspberry Pi and USB-serial adapter. Update in December 2024: It seems the newer ser2net versions use /etc/ser2net.yaml as the configuration file. This is an example of an accepter line: Connect the serial port to whatever device you want to use for […]
In order to handle SNMP traps in Zabbix you need to configure your server to receive the traps. Here are the steps, tested with Zabbix 5.4 on Debian Linux 10 (Buster), assuming Zabbix server has already been installed from the official repository: (Note: Long commands and paths below can appear split incorrectly, so be careful […]
LDAP authentication problem in the customer environment: The error message was received right after entering the password. Tshark says: 1 0.000000000 192.168.99.200 → 10.10.10.10 TCP 74 44780 → 3269 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 TSval=2891116193 TSecr=0 WS=128 2 0.001225814 10.10.10.10 → 192.168.99.200 TCP 74 3269 → 44780 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 […]
This is a small note to keep the links to posts by Peter Wu: Extract pre-master keys from an OpenSSL application Extracting openssl pre-master secret from apache2 Example in Debian Buster: With the keys saved by that process (and doing the packet capture at the same time, in either server or client side), you can […]
A short memo how to backup any PostgreSQL database: In .pgpass (you should keep this file protected): netbox-db-backup.sh: That will also find and delete backup files older than MAXDAYS.
Since Debian 10 Buster there is no minor version number in lsb_release output or /etc/os-release anymore. Bug has been filed, but apparently there is no will to get the full version number back. The dist() and linux_distribution() functions in the platform module in Python have been deprecated in 3.5 and removed in 3.8.0: Also, the […]
My trusty old VDR box started behaving erratically: sometimes the IR remote didn’t do anything. Rebooting the whole box usually helped, but not always. Eventually I was able to narrow the problem down: for some reason the LIRC serial driver did not correctly detect the IR receiver in the serial port at the boot. I […]
These are just small hints and memos what to do on a Debian Linux setup. This is not a complete guide on doing a secured routing environment with Linux. /etc/sysctl.conf: net.ipv4.ip_forward=1 Configure /etc/network/interfaces iptables -t nat -A POSTROUTING -o <upstream_interface> -j MASQUERADE apt-get install iptables-persistent apt-get install iftop apt-get install conntrack conntrack -L -s 10.11.1.10 […]