Somebody recently nudged me into the direction of NVIDIAs Bluefield 2 cards being a weird but fun system to play around with, so I did exactly that and I wanted to get rid of the vendor kernel and instead use a modern(ish) distro with a mainline kernel. Funnily enough that wasn’t actually too hard. In my case I got some DELL cards, part number 0JNDCM. They have 32GB of memory and 128GB of…
During my work for the Mobile Communications Lab at Hochschule Bonn-Rhein-Sieg I found some rather severe security vulnerabilities in AeroHive/Extreme Networks WiFi access points. It all started with a few cheap used devices whose firmware I wanted to take a closer look at to make them more suitable for a few use cases I had in mind. While digging around I stumbled over multiple vulnerabilities,…
I had problems changing the boot logo on my ThinkPad X13 the official way. Using the Windows updater it silently failed, always showing the original logo instead. Using the bootable ISO updater it just showed various error messages (that had 0 results on google, wtf). After some playing around I found a reliable way. Prepare boot logo First of all prepare your boot logo. Lenovo says it can be JPG,…
Einleitung Ich beschreibe hier kurz in eigenen Worten wieso bei dem Facebook-Ausfall am Abend des 04.10.2021 mehr betroffen war als nur die Facebook-eigenen Dienste. Ich arbeite nicht für Facebook, ich habe hier nur Informationen gesammelt und versuche diese in einfachen Worten weiterzugeben. (Extrem)Kurzeinführung BGP Im Internet gibt es Routen, diese geben an wie bestimmte Ziele erreicht werden…
TLDR: dehydrated will move, the license will NOT change, and I will still take care of the project A few days ago I was approached by Julian from apilayer who told me that they wanted to buy dehydrated as a project and that they would even like to pay me to continue working on it. At first I thought it was a joke, but Julians profile seemed legit and after a few messages it was clear they really…
I ordered an SC2016 at online.net yesterday, and wanted to reinstall it with encrypted rootfs. All my other servers had KVM consoles and possibilities to mount CD images, but this one only had a serial console and a rescue system, so I had to be a little bit creative. In the end the solution was to download the netboot image, load it with kexec and boot into that minimal system, after that I was…
Just a quick note on how to reconfigure fan speeds on an ASRock C2750D4I (and similar) board without rebooting into BIOS. Changes made this way should be kept over reboots but will be lost on powercycle (stored in volatile IPMI memory). ipmitool raw 0x3a 0x01 0x(AA) 0x(BB) 0x(CC) 0x(DD) 0x(EE) 0x(FF) 0x00 0x00 AA: CPU_FAN1 BB: CPU_FAN2 CC: REAR_FAN1 DD: REAR_FAN2 EE: FRNT_FAN1 FF: FRNT_FAN2 0x00…
In the last post I showed you how to configure an Ubiquiti EdgeRouter to use kernelmode PPTP. This post will be a continuation on the general config, showing how to set up the local network. Parts of this post may be specific to the configuration for Studierendenwerk Bonn, but most should work everywhere. Also this probably isn’t complete, I just wanted to provice a little insight for people…
I’m currently living in a building of Studierendenwerk Bonn and for our internet connection we have to use a PPTP client. As a big fan of the Ubiquiti EdgeMax series of routers I wanted to use my EdgeRouter PoE for this, but there is a problem: PPTP on EdgeMax devices is running in Userland, and it is slow, very very slow. Of my 100Mbit/s connection i was only able to get around 12Mbit/s,…
Trusted SSL certificates used to cost money, but in the past companies like StartCom already started to hand out domain-verified certificates for free, but now we have Let’s Encrypt, which takes a different approach. How it used to work in the past Getting one of those certificates usually involved signing up for an account, starting a domain verification by letting StartCom send you a pin…
In this blog post I’m going to explain how to replace a broken USB-stick in Ubiquiti EdgeMax Routers or in this case the Ubiquiti EdgeMax EdgeRouter-POE. This guide can also be used to recover from a failed firmware update. First thing you have to do is to get a new USB-stick. The stick has to be very slim (basically not wider than the USB-port itself). Also you have to be a bit careful as…
If you have multiple users on a single machine every user can normally see all running processes, their own, other users processes and even system processes. Sometimes people append sensitive data like passwords to a command, and since you can see the process list you’ll also get that password, which isn’t good. One solution would be to teach all your users to never ever do this, as if…
Just a short note for myself… To move a dpkg-managed file out of the way: dpkg-divert --rename --divert /usr/share/initramfs-tools/dropbear.original /usr/share/initramfs-tools/scripts/init-premount/dropbear Copy and edit original. cp /usr/share/initramfs-tools/dropbear.original /usr/share/initramfs-tools/scripts/init-premount/dropbear ed…
I have a few devices that support (passive) power-over-ethernet, and I quite like that as I don’t need a power supply for every single device filling up my power strip and I even can mount devices further away where there is no power available. The Raspberry Pi board normally has two ways of getting power: You can either connect a Micro-USB cable, or you can use the GPIO headers to inject…
Note: This is a slightly updated version of the old blogpost (re-written on 2016/01/25). I really like IP-KVMs. They are great devices that allow you to directly connect to and control your computer from basically anywhere in the world, even if your system crashed or your network card died. Also you can access the bios settings and raid configuration utilities which wouldn’t be possible with…