Hello,I have a single Exchange Server 2003 and have configured it to be an RPC proxy server (server.mydomain.local). I can not get my external PC to connect using Outlook 2003. I get an error "Name Could Not Be Resolved". I am connecting using a seperate domain name https://owa.mydomain.com (owa is pointing to the correct public IP on our network). Keep in mind that I can connect to this IP just fine for OWA using http://owa.mydomain.com/exchange I have been through all the MS documents describing how to configure this, but still can not get it to work.Any help would be appreciated.Thank you.

I assume you have ports 80 and 443 published/NAT'd through your Firewall to your exchange server.Make sure your external PC is using a publicly available DNS name (yourcompany.com not yourcompany.local)Check IIS. Is the site used for RPC set to only respond to a specific host header? Try adding your externally resolved domain name.

Issue description: RPC over HTTP not working for a single exchange 2003 server with error Name Could Not Be Resolved on the external outlook client 1. After reproduce the issue, check the application log for related error event on the server and client 2. If users receives the error look like The name could not be resolved. The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action when they configured the mail profile, please check this article 3. On problematic external client PC, launch outlook, hold down the CTRL key on the keyboard and click the Outlook icon in the notification area of the Windows taskbar, also known as the notification area. Check the Connection Status 4. Please use this link to test the RPC over HTTP connectivity externally 5. Please try to use the RPC over HTTP internally Related KB with same error info: You may receive a "The name could not be resolved" error message and Outlook 2003 unexpectedly quits after you log on to a network over the Internet in Windows Server 2003 How to troubleshoot connectivity issues that are caused by RPC client protocol registry entries

I purchased a Secure Certificate for $30 from GoDaddy.com and this solved the issue. No other changes were made. Thank you for all the suggestions.