When changing the IP address of a server (Windows 2003 Small Business Server)  in the network properties tab does not update the IP address for services such as DNS, WINS, DHCP, etc. In order to properly change the IP, do the following:

1. Start -> Control Panel -> "Administrative Tools" -> Server Management
   
2. Click on "Internet and Email"  branch
3. Click on "Change Server IP Address"
   
   
   This will update all the services with the new IP address