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Re: CONNECT-test: idea for someone interested in joining in

From: Christian Hägele <>
Date: Mon, 19 Dec 2011 14:26:07 +0000 (UTC)

Daniel Stenberg <daniel <at>> writes:

> I've started this work now. Seems to work pretty good already. Soon ready to
> be tested by others!

I can give you a hint about an issue I once stumbled regarding the
implementation of CONNECT on proxies:
When the client send the TCP-shutdown-send(shutdown(SD_SEND)) to the proxy the
proxy is *immediately* closing the connection to the server even if a transfer
is currently running. This can be a pitfall is someone relies on the TCP four way
shutdown of a connection, because this doesn't work with TCP-connection through a
proxy using the CONNECT-keyword. The worst thing about it is that the client
doesn't know that data was lost because the TCP-connection between client and
proxy was closed gracefully. And if no transfer is going on the connection
between server and proxy is closed gratefully, too. Only when the server is
currently sending data to the proxy the connection between server and proxy is
reset with error.
(I tested this on MS-ISA-Server, Squid2 and Squid3 which should cover 90% of all

That's just additional information which might be useful for your implementation.



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Received on 2011-12-19