How to store 50000 mails in 10MB to fight Spammers

For those who do not allow their mails being read by a large cloud provider, fighting junk mail is an endless task. And, many people developed various – sometimes really clever – techniques to mitigate it. Though, current spam filters are typically time-consuming to configure, consume immense resources (or deliberatly do not use all available information), and are complex in maintenance.

This text is about Sisyphus, a novel filter that automatically learns all (!) your mails’ content to effectively fight off junk, is easy to deploy (one binary), and just needs one line of config, the location of your mail directory.

Harddisk Encryption with Geli

This is a tutorial to guide you through the setup of a fully encrypted laptop with FreeBSD, Geli, and a separate boot/key flash drive.


Bapu provides a graphical interface to manage your virtual machines on Gandi.

Checksum a DVD

Sometimes you get a DVD that you would like to checksum. For example one to install a new operating system.

Poor Man's SSH

A poor man’s alternative to using SSH is to combine socat with spiped.

Replace a Harddisk

Here, we explain how to move from an old disk to a new one.

Connectivity to HSG

This page explains how to connect to the network of the University of St. Gallen.


Auditing is pretty useful, here is how to turn it on.

Hardening FreeBSD

Some things to remember – unfortunately far from being complete.

Secure Communication via Tor

Tor allows you to surf anonymously. It can be used not only for normal HTTP traffic but for SSH connections as well. The following is a quick installation guide.

My favorite operating system is FreeBSD. This server runs on it and I maintain several ports. Since September 2011, I am a FreeBSD ports committer under the alias cs@. Next to my FreeBSD activities, I write and publish regularly opensource code.