iis - Windows authentication for Mac browsers -

i encountering following issue when trying configure intranet asp.net site in iis 8.5 windows authentication. have iis windows authentication provider settings set to:

• negotiate
• ntlm

this works great windows-based browsers - users logged in seamlessly. mac-based browsers don't seem support negotiate protocol; when accessing site prompted domain credentials. when responding correct credentials, browser responds authentication challenge "ntlm xxxxxxx...". iis doesn't , responds 401. sends browser authentication loop prompted credentials endlessly. if click "cancel" (depending on browser in), 401 response (not useful).

if modify settings , remove "negotiate" provider, still prompted when accessing site mac browser, time ntlm challenge succeeds , can authenticate. problem getting authentication prompt windows browsers well.

is there way around (do have windows authentication misconfigured)? fine having answer credential prompt mac vast majority of users accessing windows, prefer still "invisible" log on experience.