Cisco AP Certificate expired

By | September 3, 2022

You might have some old Cisco APs like an Aironet 1142 or 1132, and you can't them join to a Cisco WLC, because the manufacturer installed certificates (MIC's) on the APs are expired. So you have two options. If your controller's software version is high enough, it will understand the following command, which will allow… Read More »

DTLS_set_timer_cb in OpenSSL 1.1.1

By | August 29, 2022

A few years ago I had problems connecting a Cisco 1131 LWAP to an Open Source CAPWAP WLC and figured out a hard coded DTLS timeout of one second in the Open SSL library as the reason. So at that time I asked in the OpenSSL developer forum, if this could be made configurable, but… Read More »

An AVL Tree im plementation in C

By | May 15, 2020

Here is an AVL tree implementation, a library called libmavl. You can download the source code as tarball: Also you might want to run tests which requires to install libmutests you can download here: You can browse the sour code via web:

Determine default Gateway obtained via DHCP under FreeBSD

By | November 1, 2019

So, lets have a FreBSD installation that got an IP address via DHCP using dhclient, and you want to know in a shell script the assigned default gateway for the specific interface. You can use the following little script which prints the IP address of the default gateway to stdout. Assuming you have the script… Read More »

Category: OS

Creating a VirtualBox Machine to Install Plan 9

By | January 16, 2019

Creating a VM in VirtualBox to run the Plan 9 operating system is pretty straightforward. Create a new virtual machine of type "Other" and version "Other/Unknown", then click "Next". Select a memory size of your choice. This could be in a range from 32 MB to what your host is able to serve. In our… Read More »

How to edit OpenSeSim Source Code in Netbeans

By | September 4, 2018

OpenSesim is an open source stock exchange simulator, where you can find the source code on Github here. To work with the source code on OpenSesim it's recommended to use the Netbeans IDE. If you are using Ubuntu 18.04, you can find here instructions to install Netbeans. You can clone the source directly in Netbeans.… Read More »

Install Netbeans 8.2 on Ubuntu 18.04

By | September 3, 2018

First you have to install OpenJDK 8 because Netbeans doesn't work with OpenJDK 11 which is installed on Ubuntu 18.04 by default. sudo apt-get install openjdk-8-jdk Next download here the Netbeans installer of your choice for Linux. If you chose Netbeans IDE Java SE you should get the file: Now start the installer, setting… Read More »