Autodiscover Service (POX)
The POX Autodiscover service provides a mechanism that allows you to use “plain old XML” (POX) messages — that is, messages that consist solely of XML payloads without any enclosing SOAP envelopes — to automatically configure Microsoft Exchange Server 2010 client applications to access the Client Access server. Autodiscover provides a powerful tool for configuring client application profiles used to discover Exchange Web Services (EWS) and associated mailbox information. Autodiscover provides configuration information inside or outside firewalls. In addition, Autodiscover will work in resource forest and multiple forest scenarios.
For Exchange 2010 and later versions, we recommend that you use the SOAP Autodiscover services instead of the POX Autodiscover service for the following reasons: