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From d...@ast.cam.ac.uk (David Robinson)
Subject Re: more Keep-Alive - possible problem
Date Mon, 12 Feb 1996 11:20:00 GMT
>> Yuck yuck. It just gets worse.
>> I've just checked netscape-2, and it sends
>> Proxy-Conenction: Keep-Alive
>> when it thinks it's talking to a proxy.
>
>Yeah -- I was about ready to strangle Lou when he told me about that
>last month.  The whole purpose for having a single Connection header
>is so that proxies can remove it without knowing what the options mean.
>Netscape will have to change their implementation, since it doesn't
>even solve the problem.
>
>> Having two different Connection headers seems really broken.
>> The client is really not in a position to choose which to use.
>> Presumably it uses Proxy-Connection: if it is configured to connect to
>> a `proxy'. But what if the proxy is in fact the origin server?
>> This implies that the header semantics must change depending on whether
>> a server (me.com) receives
>> http://me.com/path or /path in the request.
>> Thus the first form cannot be allowed for non-proxy requests (as the
>> HTTP/1.1 draft would imply).
>> 
>> But what's worse is the other case, when netscape thinks its talking to
>> the origin server, and hence uses a Connection: header, but in fact
>> this server is a gateway to another. CERN and my proxy module can
>> both work in this mode; a local request for /mirror/other/fobar
>> would be sent of as a request to http://other.com/fobar with all the
>> incoming headers. This will break if the remote server supports
>> keep-alives.
>
>Yep, it is a real mess now....

It's clear that the implementations were never thought through.

Someone must have thought 'we can't send Connection: to a proxy, what
if it forwards it to a Keep-Alive able origin server? We'd better
use Proxy-Connection: for that case'... without wondering if the
proxy server might ever forward the Proxy-Connection header to another
proxy which did support keep-alives.

So if the UK or New Zealand upgraded their country-wide proxy-servers to
one which supports keep alives then individual sites' proxy servers would
break when talking to it...

 David.

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