I’ve seen a number of questions on ISA 2004 SP2 and how it might be interfering with iTunes. I haven’t had a chance to test this out myself, as I used Rio MP3 players and MSN music (that way I avoid the "Apple Tax"). Nonetheless, a lot of you out there use iTunes and you’re in a dire fix if you’ve applied ISA 2004 SP2 to your ISA firewall.
Before I was telling folks to unbind the Web proxy filter from the HTTP Protocol Definition and then configuring the site for Direct Access. However, it appears there is a better way!
For the answer, check out Adina Hagege’s solution on the ISA Team blog over at https://blogs.technet.com/isablog/archive/2006/03/30/423600.aspx