This article was previously published under Q312955
SYMPTOMS
When you use a Windows XP-based computer to connect to the
Microsoft Windows Update Web site (at
http://windowsupdate.microsoft.com), the connection may
not succeed if you connect to the Web site through an
authenticating Web proxy that uses integrated (NTLM) proxy
authentication.
CAUSE
Windows Update uses ActiveX controls to determine which
updates are installed on your computer. These ActiveX
controls do not properly use HTTP keep-alive headers if
Microsoft Internet Explorer is configured to use HTTP 1.0.
Because integrated (NTLM) proxy authentication requires a
persistent connection to authenticate the client, the
connection may not succeed when NTLM authentication is
performed with the Web proxy.
RESOLUTION
To resolve this issue:
Start Internet Explorer.
On the Tools menu, click Internet Options.
Click the Advanced tab.
Select the Use HTTP 1.1 through Proxy Connections check
box, and then click OK.
Quit and then restart Internet Explorer, and then try to
connect to the Windows Update Web site again.
Because HTTP 1.1 uses persistent connections by default,
the entire NTLM handshake takes place on the same TCP
connection and the proxy authentication succeeds.
STATUS
Microsoft has confirmed that this is a problem in the
Microsoft products that are listed at the beginning of
this article.
The information in this article applies to:
Microsoft Proxy Server 2.0
Microsoft
