Articles in Category "GNU/Linux"

Generate Certificate Signing Requests (CSRs) for TLS Server Certificates

Overview In this article, a procedure is described to generate multiple certificate signing requests (CSR) for TLS servers, such as SMTP-, IMAP- or HTTP-servers, so that we can submit them to a Certificate Authority (CA). The CA will eventually perform the signature and return a public certificate to us. A Shell and the software OpenSSL […]

Methods of HTTP Caching

Preface I find the world wide web and the spectrum of methods and instruments that make it happen full of dubiousness and opportunity alike. Caching is generally known as one of the „hard problems“ of information science, and this is not different when it comes to technologies of the web. The text presented here, as […]

Python3 GTK3 TextView Drag-and-Drop Example

Just a small finger exercise …

Bourne to Bourne Again Shell Forward Compatibility

Introduction In this article i try to find out, if Bourne Shell scripts are runnable in Bourne Again Shell without modification. If not, i advice on how to modify the code so that it runs on both Shells. An interpreter for some variant of Bourne Shell is available as an executable /bin/sh on most Linux […]

Comparing Distinguished LDAP Names

In a Bourne Shell script, a distinguished name (DN) for performing an LDAP-query is held in a variable: dn=“cn=Malmø,ou=County Capitals,dc=Sweden,dc=Europe“ For the purpose of demonstration, this example DN contains a non-ASCII character. Let’s write a Bourne Shell function that escapes such special characters as requested by RFC 4514 using perl’s Net::LDAP::Util: canonical_dn() { perl -s […]

Determining User Access on a Linux Filesystem with „Classic Permissions“

Introduction Looking at a Linux filesystem, checking if a certain file or directory is accessible for reading, writing or executing by certain users or groups poses interesting challenges. Let the basic and seemingly simple question be: „Given a user X and a file Y, can it be determined if X has access to Y, and […]

AD-Precreation using ktutil, kinit and adcli

Using computer object precreation you can enable machines to join an Active Directory domain with knowledge of just one dedicated one-time-password. Combined with delegation you can offload management of computer objects to an otherwise unprivileged AD user.

Drawing a Yellow Rectangle on Android

As an addendum to my previous article, there now also is an Android App „YellowRectangle“ that draws a yellow rectangle and terminates on the first touch event. It runs on Android version 4.0.3 (Ice Cream Sandwich MR1) and upward. It is written in Java and C++ and uses the Allegro game development library (http://liballeg.org/).