Dijjer is a peer-to-peer HTTP cache, designed to
allow the distribution of large files from Web
servers while virtually eliminating the bandwidth
cost to the file's publisher. Dijjer is designed
to be simple, elegant, and to cleanly integrate
with existing applications where possible. Dijjer
uses "UDP hole punching" to allow it to operate
from behind firewalls without any need for manual
reconfiguration. Dijjer's distributed and scalable
content distribution algorithm is inspired by
Freenet.