Home Server with Public IPv6 Address behind Fritz!Box

Overview Situation An internet connection which uses native IPv6 and supports IPv4 through Dual-Stack Lite. The internet provider assigns the Fritz!Box an IPv6 prefix (/59). A server running Debian 12 should be publicly reachable to provide some services. Due to the Dual-Stack Lite, IPv6 is the only way to publicly expose the server. In the Fritz!Box a corresponding fort forwarding is configured. Problem There’s no control over the assigned IPv6 prefix and it might change whenever the internet connection gets reconnected. As the server has a static local IPv4 address, the second part of the IPv6 address should also be static. ...

December 22, 2024 · 2 min

Debian 12.3: data corruption with ext4 and kernel 6.1.64-1

The rollout of Debian 12.3 has been paused due to a data corruption issue in the 6.1.64-1 kernel when using the ext4 filesystem: https://www.debian.org/News/2023/2023120902 For amd64, the affected package is linux-image-6.1.0-14-amd64 as it ships kernel 6.1.64-1. It can be prevented from being installed, by setting the Pin-Priority for this version to -1: $ cat /etc/apt/preferences.d/2023-12-10-kernel-ext4-bug # https://www.debian.org/News/2023/2023120902 Package: linux-image-amd64 Pin: version 6.1.64-1 Pin-Priority: -1 Package: linux-image-rt-amd64 Pin: version 6.1.64-1 Pin-Priority: -1 This can be verified using apt-cache policy: ...

December 10, 2023 · 1 min

Review: Star Labs StarBook Mk VIr2

I recently ordered a StarBook Mk VIr2 from Star Labs : StarBok Mk VIr2 The StarBok Mk VIr2 The StarBok Mk VIr2 has the following specs: 64 GB DDR4 RAM @ 3200 MHz (2×32 GB) i7-1360P @ 2.20 GHz 2 TB Gen4 PCIe SSD 14" display Ubuntu LTS 22.04.02 coreboot (instead of AMI firmware) US keyboard layout In comparison, my daily driver for many years has been a Lenovo ThinkPad T470s with the following specs: ...

November 23, 2023 · 7 min

Debian Buster: Enable TTY inside KVM guests

When spinning up a new Debian VM using KVM virsh console <vm> does not work. The VM needs a running TTY for this: systemctl enable serial-getty@ttyS0.service systemctl start serial-getty@ttyS0.service

January 12, 2020 · 1 min

Chrome 56: Install and use Extensions

Starting with Chrome 56 on Debian you might end up having no Extensions. To re-enable them again you have to start Chrome with --enable-remote-extensions To make this a default add this flag to the default flags in /etc/chromium.d/default-flags: # Enable extensions export CHROMIUM_FLAGS="$CHROMIUM_FLAGS --enable-remote-extensions" Reference: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=851927

March 1, 2017 · 1 min

Waiting for server to accept SSH connections

Sometimes you need to wait for a just booted server to accept SSH connections. This can be solved with a one-line bash script: until nc -w 10 -z $SERVER_IP 22; do echo "SSH not available" && sleep 5; done

October 22, 2016 · 1 min

npm install fails with "npm ERR! tar.unpack untar error"

Problem npm failed randomly while installing packages. It didn’t matter which packages or if running on Debian itself or inside virtual machines using Ubuntu (vagrant). Upgrading npm to the latest version (sudo npm install -g npm@latest ) and clearing npm’s cache (npm cache clean ) didn’t help either. After examining the downloaded temporary packages in /tmp I realized that they were corrupt. The corrupt packages changed randomly on every download attempt. Changing the temporary directory from /tmp to another location did not resolve the issue. Every user on the machine was affected by the problem. ...

April 25, 2016 · 2 min

Simulate the environment of Cron Jobs

Often you will find yourself in the situation that one of your cron jobs works perfectly if you execute it manually but fails as soon as is gets executed by cron. The root cause might be the different environment. To simulate the environment of a cron job add the following entry to your crontab using crontab -e. This will create the file cronenv in your root directory and dump all available environment variables into it. Once the file was created remove the entry from your crontab and take a look at its contents: ...

March 21, 2016 · 1 min

Gnome 3: Minimize, Maximize and Close on the left

gsettings set org.gnome.desktop.wm.preferences button-layout 'close,maximize,minimize,close:'

October 11, 2015 · 1 min

Debian 8: gdm3 crashes instantly with "Oh no! Something has gone wrong"

After upgrading several Gnome 3 (and other) packages and rebooting I was unable to get to the gdm3 login screen. It crashed instantly with the message “Oh no! Something has gone wrong”. After checking various log files and consulting the internet I found a bug report which provided a (very simple) solution: sudo adduser Debian-gdm video That’s it.

October 8, 2015 · 1 min