Microsoft published Exchange Remote Connectivity Analyzer tool. Itâ??s will help you test your Exchange connection from Internet.

The tool will allow you to remotely test the following services:
1. Microsoft Exchange ActiveSync Test
This test will simulate the steps a mobile device uses to connect to an Exchange Server using Exchange ActiveSync.
2. Microsoft Exchange ActiveSync AutoDiscover Test
This test will walk through the steps a mobile device uses to connect to the AutoDiscover Service.
3. Microsoft Office Outlook 2007 Autodiscover Connectivity Test
This test will walk through the steps Microsoft Office Outlook 2007 uses to connect to Autodiscover.
4. Microsoft Office Outlook 2003 RPC/HTTP Connectivity Test
This test will walk through the steps Microsoft Office Outlook 2003 uses to connect via RPC/HTTP.
5. Inbound SMTP Email Test
This test will walk through the steps an Internet e-mail server uses to send inbound SMTP email to your domain.

The tool is available at https://www.testexchangeconnectivity.com/