Configure Proxy Settings for WinHTTP

Applies to: Exchange Server 2010

Topic Last Modified: 2011-03-19

In Microsoft Exchange Server 2010, transport servers rely on the underlying Microsoft Windows HTTP Services (WinHTTP) to manage all HTTP and HTTPS traffic. Both Hub Transport servers and Edge Transport servers may use HTTP to access updates for Microsoft Exchange 2010 Standard Anti-spam Filter Updates and the Microsoft Forefront Security for Exchange Server anti-spam update service, and for certificate revocation list (CRL) validation.

In most organizations, a proxy server is used for HTTP and HTTPS communications with destinations on the Internet. If your organization uses a proxy server and your Exchange transport servers aren't configured to use the proxy server for HTTP and HTTPS, you must configure them so that HTTP-enabled CRL validation works.

The simplest way to configure WinHTTP is to use ProxyCfg.exe. ProxyCfg.exe is a command-line tool included in the %System32% directory on all computers running Windows Server 2008 or Windows Server 2003. You can use ProxyCfg.exe to set and view WinHTTP configurations.

Looking for other management tasks related to anti-spam and antivirus features? Check out Managing Anti-Spam and Antivirus Features.

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Hub Transport server" and "Edge Transport server" entries in the Transport Permissions topic.

This example specifies that HTTP servers and HTTPS servers are accessed through the proxy server proxy_server, except for host names that don't contain a period specified by the "<local>" argument.

proxycfg -p proxy_server "<local>"

Even if you aren't running a proxy server, we recommend that you use ProxyCfg.exe to check whether a previous proxy has been set. You can view the current configuration by running the tool without arguments.


This example configures a direct Internet connection for WinHTTP or removes an existing proxy configuration.

proxycfg -d 
You must restart the Microsoft Exchange Transport service and the Microsoft Exchange Anti-spam Update service after you have made configuration changes to WinHTTP.

For more information about how to use ProxyCfg.exe, see ProxyCfg.exe, a Proxy Configuration Tool.