HOWTO Keep a network of Debians up-to-date

This article was first written in August 2005 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/289).
Due to the unrivaled apt tools, Debian is probably the easiest GNU/Linux distribution to keep up-to-date, at least when you have a fast Internet connection. In a network of many machines, the goal is slightly different though: you probably want to take as little bandwidth as possible away from users.

cron-apt

The first part of the solution, and the easiest to setup, is to install package cron-apt which will download the packages