When you have more than one system with Ubuntu installed, and you have to install same or similar set of packages on all your PCs, you can save on a lot of bandwidth if you had some ways of sharing the downloaded packages and updates. There is an easy way to do this in Ubuntu. This is done using apt-cacher a proxy server for your package repositories. It is very easy to set up and configure apt-cacher on a PC with Ubuntu inside your LAN.