https://blog.nicoboehr.de/posts/ Recent content in Posts on Nicos Blog Hugo -- gohugo.io en-us Sun, 19 Nov 2017 09:03:00 +0200 https://blog.nicoboehr.de/2017/11/19/fedora-26-terminus-font-renamed/ Sun, 19 Nov 2017 09:03:00 +0200 https://blog.nicoboehr.de/2017/11/19/fedora-26-terminus-font-renamed/ Quick note: In Fedora 26, the Terminus font was renamed. It is now called “xos4 Terminus”. If you use rxvt-unicode, you will have to adjust your .Xresources. For my setup, the relevant line now looks like this: URxvt.font: xft:xos4 terminus:pixelsize=16 https://blog.nicoboehr.de/2017/10/30/implementing-ip-multicast-over-ethernet-with-lwip-and-chibios-on-a-stm32f767zi/ Mon, 30 Oct 2017 00:00:00 +0000 https://blog.nicoboehr.de/2017/10/30/implementing-ip-multicast-over-ethernet-with-lwip-and-chibios-on-a-stm32f767zi/ For my master’s thesis, I work with STM32F767 Nulceo-144 boards. We are using ChibiOS as operating system and needed support for IP Multicast. This blog post describes what is necessary to add Multicast support to this setup. Overall, it was a lot of fun and I learned a lot! First of all, let’s take a quick look at how Multicast works. Multicast means that we address a single packet to several peers. https://blog.nicoboehr.de/2017/05/06/request-lets-encrypt-certificates-with-ansible/ Sat, 06 May 2017 00:00:00 +0000 https://blog.nicoboehr.de/2017/05/06/request-lets-encrypt-certificates-with-ansible/ Since version 2.2, Ansible comes with the letsencrypt module. This allows you to request certificates from letsencrypt. Unfortunately, I’ve found the documentation to be a bit lacking, so I want to document what I’ve done to get this working. If your distribution doesn’t have Ansible 2.2 yet, you can very easily install it using pip: pip install --user ansible As always, this is not a copy & paste tutorial, but a collection of ideas that you have to adjust to your environment. https://blog.nicoboehr.de/2017/05/01/wallabag-and-zeit.de-paywall/ Mon, 01 May 2017 00:00:00 +0000 https://blog.nicoboehr.de/2017/05/01/wallabag-and-zeit.de-paywall/ Wallabag supports paywalls. To make the zeit.de paywall work, just add the following snippet to /vendor/j0k3r/graby-site-config/zeit.de.txt: requires_login:truenot_logged_in_xpath://aside[@class='gate']login_uri:https://meine.zeit.de/anmeldenlogin_username_field:emaillogin_password_field:pass Afterwards, add your zeit.de credentials to /app/config/parameters.yaml: sites_credentials:zeit.de:{username:"you@example.com",password:"hunter"} Important: This is a YAML file, which only allows spaces, but no tabs, for whatever reason. Then, under “Internal Settings” > “Article” set “Enable authentication for websites with paywall” to “1”. After you’ve cleaned your cache, you can now read articles of zeit.de behind a paywall in your Wallabag! https://blog.nicoboehr.de/2017/04/18/freshrss-better-integration-with-wallabag/ Tue, 18 Apr 2017 00:00:00 +0000 https://blog.nicoboehr.de/2017/04/18/freshrss-better-integration-with-wallabag/ I’ve started using FreshRSS for my RSS feeds a few days ago. It’s a great software that works pretty well for me. But there is one thing I’ve found a little annoying: I like to go through the headlines of my RSS feeds on my phone and then save the articles I want to read to Wallabag. FreshRSS already supports this through its share function, but it is a little inconvenient. https://blog.nicoboehr.de/2015/11/09/encrypting-an-android-phone-with-a-broken-usb-port/ Mon, 09 Nov 2015 00:00:00 +0000 https://blog.nicoboehr.de/2015/11/09/encrypting-an-android-phone-with-a-broken-usb-port/ I have an Android phone with a broken USB port: neither the data nor the power lines work. However, I can still charge the battery by removing it from the device and putting it into an external charging device. Apart from that, the device still works absolutely fine and I see no reason to throw it away or risk breaking it by trying to repair it. I have now decided that I want to encrypt this phone, but Android wanted me to connect it to power, even though the battery was 100% full. https://blog.nicoboehr.de/2015/01/25/controlling-your-monitors-brightness-from-your-computer/ Sun, 25 Jan 2015 00:00:00 +0000 https://blog.nicoboehr.de/2015/01/25/controlling-your-monitors-brightness-from-your-computer/ I usually have to work more than eight hours a day on my computer. Especially in winter when the sun sets early, I often would have to dim the brightness of my monitor in the evening. But because most monitor on screen menus are hard to use, I almost never do that, because I am too lazy. But if I don’t I sometimes get a headache. So I thought, it must be possible to somehow control the brightness of my monitor without using the crappy menu. https://blog.nicoboehr.de/2015/01/08/pc-engines-apu-installing-debian/ Thu, 08 Jan 2015 00:00:00 +0000 https://blog.nicoboehr.de/2015/01/08/pc-engines-apu-installing-debian/ Until now, I only ran pfSense on my PC Engines APU boards. But I now wanted to get one of them running under Debian Linux. The first challenge is creating a live Linux that starts a serial terminal on boot. I found that this was the easiest using Grml2Usb. I booted Grml on my normal PC and plugged in a USB stick. Then, using a Grml ISO image, I did the following: grml2usb --fat16 --bootoptions="vga=off" --bootoptions="fb=false" --bootoptions="console=ttyS0,115200n8" grml96-full. https://blog.nicoboehr.de/2014/10/05/firefox-disable-search-and-domain-guessing/ Sun, 05 Oct 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/10/05/firefox-disable-search-and-domain-guessing/ I don’t want my firefox to perform searches on google or similar when I don’t explicitly instruct it to do so. This is especially annoying if you enter something like sw01.mgmt.corp.client.com and firefox performs a google search on that because you didn’t configure your DNS correctly. Go to about:config and set keyword.enabled = false But that isn’t enough. If you enter something like internalapp it will complete that to www.internalapp.com… This “feature” is called Domain Guessing. https://blog.nicoboehr.de/2014/09/19/amazon-elb-and-sha-256-certificates/ Fri, 19 Sep 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/09/19/amazon-elb-and-sha-256-certificates/ With the recent SHA1 deprecation in new browsers, I wanted to start deploying SHA-256 certificates to my clients. One of them used a Amazon Elastic Load Balancer (ELB). Because I could not find any information about whether they support SHA-256 certificates, I just wanted to post that they do and it works without any problems. https://blog.nicoboehr.de/2014/08/30/statische-dns-eintr%C3%A4ge-mit-einer-fritzbox/ Sat, 30 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/30/statische-dns-eintr%C3%A4ge-mit-einer-fritzbox/ Betreibt man hinter seiner Fritzbox einen Server, möchte man ihn möglicherweise über den DNS-Namen erreichen können. Da man einem Server aber sinnvollerweise eine statische IP-Adresse vergibt, wird diese von der Fritzbox nicht in den DNS eingetragen. In einer Konfigurationsdatei kann man den Host entsprechend hinterlegen. Wichtiger Hinweis: man sollte die Konfigurationsdateien der Fritzbox nur bearbeiten, wenn man weiß, wie man eine gebrickte Fritzbox wiederbelebt. Ich übernehme keine Haftung für die Richtigkeit dieser Anleitung. https://blog.nicoboehr.de/2014/08/22/broken-reset-function-on-a-server/ Fri, 22 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/22/broken-reset-function-on-a-server/ Since a few days we have problems with a server. It sometimes freezes and the only way to make it work again is to reset it. So a few days ago I got a SMS from the monitoring system that alerted me that the server was down again. After checking, I noticed that it was really down and I decided to reset it using the Reset service of our data center. https://blog.nicoboehr.de/2014/08/21/windows-server-backup-fails-when-vhds-are-mounted-inside-hyper-v-virtual-machines/ Thu, 21 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/21/windows-server-backup-fails-when-vhds-are-mounted-inside-hyper-v-virtual-machines/ We have a Virtual Machine with Windows Server 2008 R2 that has VHDs mounted. Since we had mounted the VHDs, Windows Server Backup on the Server 2008 R2 Hyper-V host always failed. When we detached the VHDs again, the backup would run just fine. Unfortunately, Windows Server Backup once again is not able to produce a helpful error message. The only indication in the logs is the following message that at least points you to the right VM: https://blog.nicoboehr.de/2014/08/20/localized-names-of-users-and-groups-in-windows/ Wed, 20 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/20/localized-names-of-users-and-groups-in-windows/ You know the “Authenticated Users” group in Windows? Microsoft decided to localize its name. For example, in a german Windows it is called “Authentifizierte Benutzer”. While I don’t want to criticize the decision to localize the name, I want to criticize the way it is implemented in some parts of Windows. If you take a look at icacls, you can write a script that does not depend on the locale of the installed system. https://blog.nicoboehr.de/2014/08/19/why-disabling-screen-blanking-is-a-good-idea/ Tue, 19 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/19/why-disabling-screen-blanking-is-a-good-idea/ Some Linux distributions (for example Debian) in their default configuration blank the screen after a certain time of inactivity. Until recently, I didn’t disable screen blanking on my servers. But recently one server started freezing once a month or so. Unfortunately, it doesn’t have an IPMI so I have to send a technician over to have a look at it. The problem is: if the screen is blanked you cannot see the messages of the kernel and if the kernel has died, you cannot un-blank the screen. https://blog.nicoboehr.de/2014/08/18/have-ssd-and-hdd-work-together-in-your-client-computers/ Mon, 18 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/18/have-ssd-and-hdd-work-together-in-your-client-computers/ In a recent upgrade for our computer pool, we also wanted to install SSDs in every computer. While SSDs are great, they usually don’t work that well with huge amounts of data. Some of our users store 100+ GB of data on the computers. Even though SSDs are becoming cheaper and cheaper, it wouldn’t make sense to put a 1 TB SSD in every computer: it is just too expensive. https://blog.nicoboehr.de/2014/08/15/unattended-deployment-of-virtualbox/ Fri, 15 Aug 2014 00:00:00 +0000 https://blog.nicoboehr.de/2014/08/15/unattended-deployment-of-virtualbox/ At first, the unattended deployment of VirtualBox might sound quite complicated, because the installer needs to set up drivers and do quite a bit of complicated stuff. Additionally, the installer of VirtualBox offered on the website is an EXE file and not a convenient MSI file. But overall, it is quite simple to do an unattended installation of virtualbox. With a little bit of googling you can find this excellent guide on the VirtualBox website.