This chapter introduced the Autodiscover service and the two Autodiscover providers, Outlook and MobileSync. Although we discussed both providers, the Outlook provider offers the configuration information that is of interest when determining which Client Access Server a client application should use for sending Exchange Web Service requests. We discussed the various protocols exposed in an Outlook provider Autodiscover response and which protocol is used for internal as compared to external access. Outlook provider redirections were also covered. We concluded the chapter by providing a C# method that issues the Autodiscover request for you and extracts the Exchange Web Services URL from the response.