You Receive an Error Message When You Try to Start the Web Service

We strongly recommend that all users upgrade to Microsoft Internet Information Services (IIS) version 7.0 running on Microsoft Windows Server 2008. IIS 7.0 significantly increases Web infrastructure security. For more information about IIS security-related topics, visit the following Microsoft Web site:For more information about IIS 7.0, visit the following Microsoft Web site:


When you attempt to start the Web service, the following error message occurs:
Address already in use.
Also, the event log contains the following:
Event 115
Source: w3svc
Description: Could not bind instance X


Another service or application is listening to or using one of the default TCP ports (80 for http connections, 443 for https connections) that the World Wide Web Publishing Service (W3SVC) needs to bind to.


Disable or uninstall the service or application that is using port 80 or 443, and then retest the Web sites. An example of an application that could have grabbed port 80 is MSProxy or some third party application.

In Microsoft Windows XP you can determine the application that is using the port attempting to be used. To do this, issue the following command:
netstat -ano
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

281336 How to Determine Which Program Uses or Blocks Specific Transmission Control Protocol Ports
NOTE: It may be necessary to restart the computer.

Several third-party utilities are available to provide this type of functionality in Windows 2000 and Windows NT:
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More Information

To determine which ports are being listened to by other services or applications, first stop the IISADMIN service, and then type netstat -an at the command prompt.

NOTE: If this error message occurs immediately after you install IIS 5.0 over IIS 4.0, removing and then reinstalling the TCP/IP protocol from Windows may reset the TCP port registry entries to the default values, allowing the IIS 5.0 Web service to work again. However, be aware that doing so may prevent the other service or application using port 80 or 443 from operating properly.