Winsock Proxy Client May Not Start

When you are using the Microsoft Winsock Proxy 2.0 client, a Winsock program may stop responding (hang) after you reboot the computer or when you log on with a fully qualified domain name (FQDN) in the Mspclnt.ini file (as described in the "About Winsock Proxy Arrays" section in the Proxy Server 2.0 online documentation).

The program hangs when the Winsock Proxy client attempts to perform name resolution for the proxy server remotely by using the Winsock Proxy service.

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

To work around this behavior, use any of the following methods:

• Use "NameResolution=L" in the [Common Configuration] section of the Mspclnt.ini file. Note that doing so causes all name resolution to be performed locally.
• Instead of specifying the FQDN in the Mspclnt.ini file, specify only the host name part of the FQDN. Then, make sure that the computers that are running the Winsock Proxy client are configured in the same Domain Name System (DNS) domain or a child DNS domain of the proxy server, or specify the proxy server's DNS domain in the domain suffix search order.
• Run a Winsock program that does not use the Winsock Proxy client at startup.
• Use IP addresses in the Mspclnt.ini file similar to:
  [Servers IP Addresses]
  Addr1=
  Addr2=
  Addr3=

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

NOTE: This hotfix should be applied to client computers using the Winsock Proxy client with Proxy Server 2.0.

Proxy Server 2.0 creates a Winsock Proxy Client share by default: \\servername\mspclnt. To make the fix available for all present and future client machines, replace the hotfix provided wspwsp.dll file in the appropriate platform folders on the Proxy Server. By default the path to the files is: <installdrive>\MSP\Clients\Alpha (or i386 depending on the platform)