This feature requires you to use a Microsoft Exchange 2003 or later account. Most home and personal accounts do not use Exchange.
In a local area network (LAN) environment, Microsoft Outlook communicates with the Exchange server using remote procedure call (RPC) (remote procedure call (RPC): In programming, a request by one program to a second program on a remote system. The second program generally performs a task and returns the results of that task to the first program.) with Transmission Control Protocol/Internet Protocol (TCP/IP). This method provides quick, efficient access for a corporate network. However, in previous versions of Exchange server and Outlook, access to an Exchange server by remote users required a virtual private network (VPN) (virtual private network (VPN): Extension of a private network encompassing encapsulated, encrypted, and authenticated links across shared or public networks. VPN connections provide remote access and connections to private networks over the Internet.) connection to the corporate network. A VPN provides a remote user with a connection within an organization's corporate network and within its firewall. A VPN enables access to more network services than is required for just e-mail access.
For remote connections, Outlook now offers an alternative to VPN connections. Outlook can connect to an Exchange server through the Internet using RPC over HTTP. This feature allows you to remotely access your Exchange server account from the Internet when you are working outside your organization’s firewall without any special connections or hardware, such as smart cards and security tokens.
There are several minimum requirements to use this feature. These include:
- Microsoft Windows XP Service Pack 1 (SP1) with Microsoft Knowledge Base article 331320 updates installed or a later Service Pack.
- Microsoft Exchange Server 2003 running on Microsoft Windows Server 2003.
- Your Exchange server administrator must have configured the server to permit connections via HTTP. For more information about configuring this feature, see the Microsoft Office Resource Kit and the Microsoft Exchange Server documentation.