Free and Open Source Software
Many people might have heard of several common types of software, such as freeware, which is software you are allowed to use for free and (more generically), commercial software such as Microsoft Windows or Adobe Photoshop. Commercial software, generally, comes with a license restricting you to use the software in a certain way, and usually banning you from copying or modifying it.
IPCop is a type of software known as Open Source Software (OSS). As a piece of OSS, IPCop is released under a license called the GNU General Public License (GPL).
As with all Open Source Software packages distributed under this license and others like it, IPCop affords its users some basic freedoms.
Under the GPL, IPCop users are given the freedom to read, modify, and redistribute the source code of the software. The only caveat attached to this is that if you decide to redistribute this software (for instance, if you make a copy of IPCop with some improvements and give it to a friend...