ISA Proxy Client may be required to download VS 2008 SP1
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Download and install the Microsoft ISA Proxy Client. The default settings should be sufficient, but if you have doubts or questions please contact your network administrator.
The VS2008 SP1 bootstrap application relies on the Background Intelligent Transfer Service (BITS), falling back to WinHTTP then URLMon to download packages. BITS and Windows HTTP Services (WinHTTP) do not, by default, use Internet Explorer proxy settings. So even if you have Internet Explorer set to automatically detect a proxy server or have manually specified a proxy server, these protocol handlers will fail if the network administrator has enforced the proxy server; i.e., it cannot be bypassed.
These protocol handlers will attempt to automatically detect a proxy server, but if that information is not available or the system accounts were not manually configured with proxy server settings they will fail.
You can use the BITSAdmin tool to configure BITS to use automatic proxy detection or manual proxy settings like shown in the following examples.
bitsadmin.exe /util /setieproxy localsystem AUTODETECT
bitsadmin.exe /util /setieproxy localsystem MANUAL_PROXY proxy1:80 "<local>"
If BITS is not properly configured for your network proxy, you might also be getting error 0x8024402C from Windows Update.
Because BITS is robust, it is preferred to download packages for VS 2008 SP1; but if you’d like to configure WinHTTP to use the current IE proxy settings, you can use the Proxy Configuration Tool like shown in the following example.
Another solution if you’re on a network that uses ISA Server is to install the Microsoft ISA Proxy Client which should properly detect the proper proxy server settings and configure both the current user and machine accounts to use the correct proxy servers. If it does not, please contact your network administrator.
Updated: first reconfiguring BITS or WinHTTP to use the correct proxy is the recommended approach before installing the ISA Proxy Client. The ISA Proxy Client is only supported for ISA-protected networks. Since this problem is not limited to ISA proxies installing the ISA Proxy Client may not work on your network.