Thomas Dalton wrote:
This has come up before - if memory serves, the excuse given was that IE doesn't always show custom error pages (I think there is a minimum size, although I can't see how the Mediawiki pages would be shorter than that). It's something that bothers me as well - a page saying "page not found" really should return a 404 error code...
*nod*
See http://bugzilla.wikimedia.org/show_bug.cgi?id=2585
There were difficult to track down errors at the time we originally tried this, but we may have done it wrong (eg without ensuring the minimum object size for IE...) or else there may have been some sort of proxy issue that we didn't track down correctly.
Note that edit pages and view pages possibly should be handled differently, or possibly not.
There's additionally an old req in for 404 returns on Special:Export: http://bugzilla.wikimedia.org/show_bug.cgi?id=3161
That one is imho a more dubious case.
-- brion vibber (brion @ wikimedia.org)