David Sommerseth, Senior Quality Assurance Engineer at Red Hat, has been working with Linux professionally since 1998. During this time, David has completed a range of tasks, from serving in system and network administration roles to developing personalization systems for payment cards and online payment transaction handling. David currently works with the Red Hat Enterprise MRG product, mostly focusing on the real-time kernel and its related tools.

David, who is originally from Norway and currently lives in the Czech Republic, enjoys hacking on open source software and has recently become more involved in the OpenVPN development. David has big plans for his own pet project, eurephia (http://www.eurephia.net/), which is tightly connected to OpenVPN.

Krzee King is a self-taught BSD user who has been helping with OpenVPN for more than three years. He wrote one of the most widely used documents on routing lans over OpenVPN, and helps maintain the IRC channel.

Ralf Hildebrandt is an active and well-known figure in the Postfix community. He's been a systems engineer for T-Systems, a German telecommunications company, and is now employed at Charite, Europe's largest University hospital. He has spoken about Postfix at industry conferences and contributes regularly to a number of open source mailing lists. Together with Patrick Koetter, he has written the Book of Postfix.