[Privoxy-users] Connection header

[Matthew Painter]

Chrome has a Proxy-Connection: Keep-Alive header and this doesn't get
translated into a Connection: Keep-Alive header.

Chrome doesn't add the Connection header when using a proxy - but does if
hitting the site direct.

Therefore it is possible to know that the request was made through privoxy.

I have an example of this happening with a third party site where the
upstream server rejects the request.

On Sat, Jun 24, 2017 at 2:13 PM Fabian Keil <fk at fabiankeil.de> wrote:

> Matthew Painter <matthew.painter at import.io> wrote:
>
> > Wondering why privoxy doesn't include Connection header (i.e. swap the
> > Proxy-Connection header out for it) when keep-alive is turned on in the
> > config - is this by design? Currently I'm putting it back in via an
> action
> > and then using the headers sorting but seems odd.
>
> In case of HTTP/1.1, not sending any Connection header implies
> interest to keep the connection alive.
>
> If you use a client that doesn't set a "Connection: keep-alive" header,
> letting Privoxy add the header lets the request stand out (assuming
> someone is checking for header differences and/or trying to fingerprint
> clients) without providing any obvious benefit.
>
> If the header is already set, Privoxy will not remove it by default
> (if keep-alive support is enabled)  so I'm not sure why you used
> the phrase "putting it back in".
>
> You can enable "debug 8" to see what's going. If the header is kept,
> you should see messages like:
> 15:03:48.203 014 Header: Keeping the client header 'Connection:
> keep-alive' around. The server connection will be kept alive if possible.
>
> Fabian
>
-- 

-- 

*Matthew Painter*

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