CBT - Computer Based Training
It’s a new and interesting site that offers some sceencast about various arguments.
One of the most interesting is:
Linux DNS Server 38 minutes 28 seconds This video explains how to set up a DNS server on a GNU/Linux server. In the video I explain a little bit about how DNS works, then I install and configure BIND in a chroot jail on 2 DNS servers in a master/slave relationship. This video is specifically tailored to setting up DNS for a web server.