So at work were currently at 10.10.5 on all our machines (big push to 10.11 coming soon) and we currently use Safari for internal websites and firefox for external websites. So the users wanted to know why we couldn't use Safari for external websites, so I started looking into the issue.
It seems that anytime the OS tries to get to any external website, it doesn't send any authentication. This seems to be the case for Safari, iTunes, and App store. So I called our Apple rep and set up a meeting with an engineer. It lasted about an hour and pretty much to get anywhere we need to get the Tier 3 support plan (which I'm working on proposing to management). But in the meantime, I wanted to work with our proxy folks to see what the issue is. So I had a good meeting with them yesterday and we ran quite a bit of tests. It turns out the the OS is never sending authenticated messages. It keeps sending the requests as anonymous. Even though Safari/iTunes/App Store do prompt user for credentials on initial launch and they are stored in the keychain. It looks like that information is never getting sent to the proxy.
So are any of you guys seeing this same issue? Is there a fix? I don't mind talking with management about getting a tier 3 level agreement, but want to see if this is actually fixable before we shell out lots of money.