Internet Explorer 7 (and possibly other versions) swallows 403: Forbidden error
pages less than 256 bytes when "Friendly Error Messages" are turned on. Hudson
(in HudsonAuthenticationEntryPoint.java) uses a 403/Meta Refresh combination to
redirect unauthenticated users to the login form. This results in an error page
instead of a redirect.

The problem is even more prevalent when fronting Hudson with Apache/mod_deflate,
as IE considers the downloaded bytes when deciding to eat error pages, not the
uncompressed bytes.

Please add > 256 bytes of random garbage to the output from
HudsonAuthenticationEntryPoint.java to prevent this problem from bothering poor
Internet Explorer users.