# aptitude install lsb-release
# wget -q "http://repo.varnish-cache.org/debian/GPG-key.txt" -O- | apt-key add -
# echo "deb http://repo.varnish-cache.org/debian/ $(lsb_release -s -c) varnish-2.1" >> /etc/apt/sources.list.d/varnish.list
# aptitude update
# aptitude install varnish