Stefan Angrick

Monitoring a server can be a lot of work, but thankfully handy tools like fail2ban or logwatch make the task a lot easier. Fail2ban, for example, monitors the log files of services running on your system and blocks incoming connections when it detects a break-in attempt (using iptables or hosts.deny). These need to be defined using a regex filter, and while a great number of templates are already available for the most-used services (Apache, SSH, etc.), OpenVPN thus far has not been included. Setting this up isn't too difficult, though.px.gif

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I recently had to work on a Matlab assignment that required the use of fminbnd() to find local extrema. As I typically work in Octave rather than Matlab I ran into some problems getting my code to work within both programmes. As it turned out, Matlab and Octave handle the function slightly differently, so I thought I'd share my findings to save others some headache.px.gif

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I have recently been playing around with LyX and XeTeX, a Unicode extension for TeX, to find a set-up that allows me to switch easily between various East Asian languages without entering LaTeX code. With the help of a few friends, the xeCJK manual and Richard Heck over at the LyX Mailing List, I was able to define LyX Text Styles for Chinese (Simplified and Traditional text), Japanese and Korean that can be selected via the context menu right from within LyX itself, allowing me to focus on the content of my writing and leaving the worrying about Unihan issues to someone else.px.gif

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After Google's much-publicised decision to replace Google Talk with Hangouts and drop XMPP support in the process, many people have been looking for alternative XMPP servers that allow connecting through standards-based clients and support federation with other servers. Here are a few servers I recommend.px.gif

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Ever since I started using Fail2ban and Logwatch to monitor unauthorized login attempts and system logs on my server, I have been looking for an easy way to regularly receive encrypted status reports from both programmes by email. After playing around with gpg-mailgate for some time (useful tutorial here), I decided to opt for a simpler solution and told both programmes to send their reports to a specific user on my system. These messages are then retrieved by a simple cron script and emailed to me at regular intervals. Here is how I did it.px.gif

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While viruses on Linux are rare, I have always found it a sensible precaution to scan incoming messages for malware. It helps me weed out the occasional Windows virus that gets sent my way and keeps me from forwarding malicious attachments to friends. A common feature to most antivirus software for Windows, email scanning can be easily set up for most email clients on Linux. Plugins for ClamAV are available for Thunderbird (here) and Claws Mail (here), so set-up is fairly straightforward here, but the same functionality can be added to Evolution and Sylpheed by use of a simple bash script.px.gif

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I've been using Gnome Shell with Ubuntu's Ubuntu-mono-dark theme for some time. However, since the release of Ubuntu Precise Pangolin, which ships with Gnome 3.4, I've noticed a problem with the keyboard icon, which appears next to the user menu in the upper right corner when you use input methods like iBus. Right after you log on, the keyboard icon starts jumping around, changing size every few milliseconds. This usually stops at some point, but still, it's a major annoyance and enough to put some people off using the theme I imagine. There is a way to fix it, though.px.gif

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Installing a Japanese IME on Android can be a little tricky since the semi-official OpenWnn IME (jp.co.omronsoft.openwnn), which is included in Japanese Android systems, is not available on the Android Market. Sure, there are alternatives, like Simeji or various OpenWnn derivatives, but if you look carefully, you will notice that they usually do not provide their source code and list full internet access as a requirement. If you feel uncomfortable with the thought of transmitting everything you type (including passwords) to a third party, this post is for you.px.gif

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When I recently tried to open my favourite Java webcam applet in Firefox on Ubuntu Natty 11.04, I was surprised to find that it wasn't working. Issues with legacy Java applications are common now that the Java world is moving towards OpenJDK as the future standard. In certain cases you may have to use an older version of Java to get your applet to work. This will tell you how to install Sun Java 6 and set your system to use it as the default virtual machine for local Java applications and web applets in your browser.px.gif

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After a two-week long battle trying to get Realtek's RTL8188CE WiFi network card to work on Ubuntu Natty 11.04, countless reinstalls and email exchanges with Realtek's customer support, I finally managed to get Realtek's PCI Express Mini WiFi card to establish a stable connection. I figured I'd share my findings with the world and save other users some trouble.px.gif

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