Configuring MS CRM Outlook with External CRM URL Not working

Hi all,

I have configured MS CRM 2011 for MS office outlook in my  office system and i have an External URL to access our crm from home.In my  home PC I can access crm  in web client using external url. Now I need to access the CRM in my outlook. So I downloaded the "CRM2011-Client-ENU-i386.exe" and installed it. Next while  doing Configuration  I am gave the server url as my External url (http://27.108.0.125:4444) and click the test connection it gives an error  as

" the specified microsfot dynamics CRM server address(URL) is not responding.Ask your administrator toverfiy the server is turned on, and then try again"

What is the reason for this ? How to configure crm outlook for different domain users?

Thanks in Advance......

Krishn Prasad Shetty