Troubleshooting RPC/HTTP

RPC/HTTP is a fantastic solution to accessing your mail without using a VPN, and since we enabled it here at Microsoft, I hardly ever log on using the VPN and smartcard when I just need to send emails. (General emal triage is done as and where on my smartphone to avoid the Aaargh! feeling when I get back to my mails after a few days out and about.

The problem is when something along the way goes wrong with your RPC/HTTP connection.  Where to start… Well you need to be aware of how RPC over HTTP works… and how RPC/HTTP configured

1. The RPC proxy server establishes and maintains a connection to the Exchange 2003 computer.
2. The RPC proxy server sends RPC requests to the Exchange 2003 computer.
3. The RPC proxy server sends the replies over the Internet to the client program.
4. The Exchange 2003 computer responds to the RPC requests from the RPC proxy server.

To successfully connect to an Exchange 2003 computer by using RPC over HTTP, an Outlook 2003 connection process must follow this procedure:

1. The client computer must resolve the RPC proxy server name by using DNS.
2. The client computer must use Secure Sockets Layer (SSL) to connect to the RPC proxy server.
3. The Microsoft Internet Explorer program on the client computer must process the security certificate that is issued by the RPC proxy server.
4. The client computer must authenticate a connection to the RPC proxy server.
5. The RPC proxy server must contain the computer name of the destination computer. For example, the RPC proxy server must contain the name of the Exchange 2003 computer.
6. The RPC proxy server must resolve the computer names of the destination computers by using DNS.
7. The RPC proxy server must establish a Transmission Control Protocol (TCP) connection to the destination computer.
8. The user’s account credentials must be authorized by the domain.
9. The RPC proxy server must send the user’s account credentials to the Exchange information store and then log on to Exchange 2003 computer.

Quite a lot to troubleshoot eh?  So here are the high level troubleshooting steps

Step 1: Verify that RPC over HTTP support is installed
Step 2: Verify that the World Wide Web Publishing Service is started
Step 3: Verify that an SSL certificate is installed on the RPC proxy server
Step 4: Connect to the RPC proxy server by using an SSL connection
Step 5: Verify that the RPC proxy server has basic authentication configured
Step 6: Verify the client computer configuration
Step 7: Verify the Outlook profile configuration
Step 8: Verify the Exchange 2003 port configuration

The detailed steps if you want to drill in to troubleshooting the above is here