Can somebody provide me with a clear explantion of the 3 ways of authenticating an outlook account and maybe help me with this problem? The problem we are currently having is that a person internally logs on with his domain credentials and via ntml i presume which presents no problems whatsoever. Now when that same person is on location and he wants to check his mail via outlook over rpc a passwoord is asked. However when the correct password for the user is inserted it doesn't work. The password is asked over and over again as if the password is incorrect although it is. The authentication is put on basic authentication.

According to my understanding. When the users is working locally he will be using ntlm or kerberos as authentication method because its directly connected to the Exchange Server as a Mapi client and authenticates using Active Directory which mean Active directory supports both the authentication methods. While the same user if he uses rpc over http it uses IIS as the authentication mechanism thats why basic authentication comes into play. http://www.virmansec.com/blogs/skhairuddin

Hi, Thanks for the post. I think Syed explained it very well. As it is a Exchange-related issue, please re-post a new thread to our Exchange Forum: http://social.technet.microsoft.com/forums/en-US/category/exchangeserver/ Thanks, MilesPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.