I can't seem to get this right. Please help be figure out what proxy access rule needs to be added to allow this to work.

When I try to download a printer driver from HP's website using this url, I get a "504 Gateway Timeout" error.
ftp://ftp.hp.com/pub/softlib/softwar...win2kxp-en.exe

if I simply change the first part of the url to the following, it works perfectly.
http://ftp.hp.com/pub/softlib/softwa...win2kxp-en.exe

Normal FTP works fine, so I know that it isn't a packet filter issue.

Please help.