Subject: http proxy & tunnel differences ??

From: "Vinit Kumar" <[email-masked]>
Date: Tue, 26 Oct 1999 00:06:34 PDT

Hi,

RFC 2616 defines a http proxy and a tunnel. But I'am confused on how a http 
tunnel works.

A proxy works by taking a request from a client and connecting to the origin 
server indicated in the request.  Here the client is configured to go 
through the proxy.

How does a http tunnel work. Is the initial connection similar ?
Does a client (browser) need to configured differently when it goes through 
a tunnel or is it same as the configuration required when it goes through 
the proxy ? Are there to separate tcp connections for each request even in a 
tunnel ?

Thanks in Advance,

Regards,

Vinit Kumar

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From: "Scott Lawrence" <[email-masked]>
Date: Tue, 26 Oct 1999 09:27:25 -0400

> From: Vinit Kumar
> To: [email-masked]
> Subject: http proxy & tunnel differences ??

> server indicated in the request.  Here the client is configured to go

Actually, the client may or may not know about the proxy.

> the proxy ? Are there to separate tcp connections for each

The difference is in the behavior of the intermediate system (proxy or
tunnel).  A tunnel just forwards the request and the response
unmodified.  A proxy at least adds its own identification to a Via
header, and may also respond from a cache, require proxy authentication,
or any number of other proxy-specific functions.

--
Scott Lawrence           Director of R & D        <[email-masked]>
Agranat Systems, Inc.  Embedded Web Technology   http://www.agranat.com/

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From: "Roy T. Fielding" <[email-masked]>
Date: Tue, 26 Oct 1999 08:39:49 -0700

>Actually, the client may or may not know about the proxy.

The client always knows about the proxy -- that is what distinguishes
a proxy from a gateway.  A "reverse proxy" is a gateway.

>> the proxy ? Are there to separate tcp connections for each

Some tunnels are activated by a proxy request, some are simply
port forwarding TCP firewalls (either on the client side or the
server side, or both), and others are gateways to other servers.
The important thing from HTTP's perspective is that once an
intermediary becomes a tunnel, it is no longer conscious of the
HTTP communication -- only of bytes being relayed from one connection
to another.

....Roy