The dynamic host configuration protocol (DHCP) describes the means by which a system can connect to a network and obtain the necessary information for communication upon that network. The manual is available in the FreeBSD manual pages.
When the client is executed, it begins broadcasting requests for configuration information. By default, these requests are on UDP [...]

If you need to calculate the classless inter domain routing notation (CIDR) from a given IP address netmask or IP address range, there are many free online calculators available, which will do the job.
CIDR simply replaces the subnet mask, such as 255.255.240.0, which expressed as CIDR notation is replaced with /20.
We recommend the calculator at [...]

There are lots of open source software, that can be used to combine a series of raw movie clips from a digital camera into a single compressed movie clip. A simple solution is to use the command line movie encoder mencoder.
In this example, we want to combine three raw movie clips, 1.avi, 2.avi and 3.avi, [...]

This is the procedure for upgrading a WordPress installation. It is based on the procedure from WordPress. However, this procedure is optimized for those, who has direct shell access to their web server.
Backup the database.
Backup the WordPress directory, download and install the new version.
cp -r www.foobar.com www.foobar.com-backup
cd www.foobar.com
rm -rf *
ftp http://wordpress.org/latest.zip
unzip latest.zip
rm latest.zip
mv wordpress/* .
rmdir [...]

In our example, we want to set up a website, that has a log, a static page and a content management system behind it. We want to be able to change between different theme designs.
There are many of such open source systems around. We will choose WordPress for this example.
It is assumed, that system account [...]