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Re: Connection:Keep-Alive and Proxies

From: Alex Rousskov <rousskov@measurement-factory.com>
Date: Tue, 26 Nov 2002 10:33:42 -0700 (MST)
To: Scott Lawrence <lawrence@world.std.com>
cc: Diwakar Shetty <Diwakar.Shetty@oracle.com>, <ietf-http-wg@w3.org>
Message-ID: <Pine.BSF.4.44.0211261014470.19283-100000@measurement-factory.com>

On 26 Nov 2002, Scott Lawrence wrote:

> If the origin server honored the Keep-Alive it would send a
> Content-Length header in the response, and thus the end would not be
> ambiguous.

As far as I can see, the following real-world problems make the above
difficult to rely on:

	- many old HTTP/1.0 clients ignore Content-Length header
	  (because they do not really need it for anything other
	  than double checking the content validity)

	- some HTTP/1.0 servers include incorrect Content-Length
	  headers and, hence, 1.0 clients SHOULD NOT depend on the
	  Content-Length value being correct (RFC 1945, section 7.2.2)

	- under certain conditions, the origin server may not include
	  a Content-Length header and a buggy proxy may not append
	  it when downgrading to HTTP/1.0 (or it would not know that
	  it needs to downgrade because the proxy that is going to
	  get stuck has tunneled HTTP/1.1 request version or other
	  headers implying it can handle persistent connections)

Alex.

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Received on Tuesday, 26 November 2002 12:33:44 GMT

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