As administrators continue to lock down secured networks, one option is to block unwanted protocols at the firewall level. One of these protocols is RPC (Remote Procedure Call). With the configuration of RPC over HTTP, Outlook 2003 can connect to your front-end Exchange server that is sitting behind your perimeter firewall. The front-end Exchange server will then communicate with a back-end Exchange server to connect to your mailbox. You can configure the use of a certificate and HTTPS to make sure your data is secure. This allows your remote users to use Outlook but not have to connect to the network first.

For a further understanding I recommend enrolling in Course 2400 - Implementing and Managing Microsoft® Exchange Server 2003

For further reference refer to the following information available from Microsoft's website:
http://office.microsoft.com/en-us/assistance/HA011402731033.aspx
http://www.microsoft.com/technet/prodtechnol/exchange/2003/library/ex2k3rpc.mspx
http://support.microsoft.com/?kbid=833401

About Doug Niles
Doug Niles is a Microsoft Certified Trainer who has taught thousands of IT professionals from some of the world's largest organizations. Doug trains IT professionals and helps them to understand, implement and deploy Microsoft desktop and server infrastructure products.

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