Kloxo is a lightweight and powerful Web hosting panel that has been in development since 2002. It was formerly known as LxAdmin. It allows for adding customers, resellers, and wholesale resellers with few clicks. Clustering functions are also built in, so you can expand and add servers whenever you need. Migrating customers between servers is easy and automatic, making it the most extensible panel to date. The services installed by default are Apache, BIND, MySQL, Pure-ftpd, Qmail, and Bogofilter. You can also switch between Apache and Lighttpd, BIND and djbdns, Bogofilter and Spamassassin. All configuration files are converted automatically in the process.
The Taridium ipbx is a complete software-based VoIP PBX system that replaces a traditional proprietary hardware PBX. It runs on Linux without the need for extra software licenses, and is based on the SIP standard. It supports many phones and is available for free in a 5 user version.