PRB: AddResponseHeaders and AddHeader Are Not Supported on Proxy Server (303677)


The information in this article applies to:

  • Microsoft Proxy Server 2.0
This article was previously published under Q303677

SYMPTOMS

Normally AddResponseHeaders and AddHeader can be used in an Internet server application programming interface (ISAPI) filter to add an HTTP header to the outgoing response. However, if the ISAPI filter is installed over Proxy Server, these two functions do not work.

CAUSE

Proxy Server version 2.0 is an ISAPI extension over Internet Information Server (IIS) version 5.0, so ISAPI filters that are installed over Proxy Server 2.0 are actually installed over IIS as well. IIS allows access to HTTP response headers using AddResponseHeaders and AddHeaderonly when IIS parses the HTTP header. In the case of Proxy Server, IIS does not parse the response for performance reasons, so these functions are not called.
Modification Type:MajorLast Reviewed:7/17/2001
Keywords:kbprb KB303677
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