Package: snapshot.debian.org Severity: normal | weasel@intrepid:~$ wget -O /dev/null -S http://snapshot.debian.org/archive/backports.org/20100719T095641Z/dists/lenny-backports/contrib/binary-amd64/Packages.diff/Index .. | Cache-Control: no-cache There's no reason why such a 404 should not be cached, in fact, there's very good reasons why it should. Probably want to make it publicly cachable, for at least a day or so.