http://debaday.debian.net/2008/11/09/apt-p2p-peer-to-peer-downloading-of-debi...
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Do you want to help out the Debian (or Ubuntu) project with some mirror bandwidth but don’t know how? Do you want to contribute somehow to Debian’s infrastructure, but you’re not a coder? Tired of getting slow download speeds when the mirrors are overloaded after a new release? Then Apt-P2P is for you.
After installing the apt-p2p package and making some minor changes to apt’s sources, all the files you download with apt (or aptitude, synaptic, gnome-apt, etc…) will be shared with other users, and any files you download will use other users (peers) to download from. However, if no other users have the file you want there’s no need to worry, Apt-P2P will happily fall back to downloading directly from the mirror so your download will not fail.
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