Re: [squid-users] IP passthrough the cache

From: Marc Elsen <marc.elsen@dont-contact.us>
Date: Wed, 22 Jan 2003 15:24:40 +0100

Laurent HENRY wrote:
>
> I mean it works using the remote application and passing by the proxy.
> so i guess it passes by the proxy but the end application doesn't see the
> proxy address and know it is for one of it registred client.

 Yes, that is normal because ip-wise, if SQUID is-in-place
 then any packet has source ip address of the proxy.
 It was discussed in the past , whether squid could forge
 the ip address of the client in the ip packet.
 
 This of course , is impossible , because if
 you look at the network stack, it is an application.
 Meaning that is has no access to ip source and destionation field
 in an ip packet.

 M.

>
> in my squid.conf :
> forwarded_for on
>
> Le Mercredi 22 Janvier 2003 15:01, Marc Elsen a écrit :
> > Laurent HENRY wrote:
> > > Hi,
> > > thank you for your answer. Unfortunately, i told them the same but they
> > > don't seem to give a damn about my complains.
> > > What i don't understand is what (without any special squid configuration)
> > > it works with some workstations (Win$) and some not at all(MacOs/Linux).
> >
> > Not sure what you mean by 'it works' here, you mean just Internet
> > access or using the remote application ?
> >
> > > Can you tell me more about the X-Forward and the use of it in this
> > > particular bad case ?
> >
> > From squid.conf.default
> >
> >
> > # TAG: forwarded_for on|off
> > # If set, Squid will include your system's IP address or name
> > # in the HTTP requests it forwards. By default it looks like
> > # this:
> > #
> > # X-Forwarded-For: 192.1.2.3
> > #
> > # If you disable this, it will appear as
> > #
> > # X-Forwarded-For: unknown
> > #
> > #Default:
> > # forwarded_for on
> >
> > It remains at the discretion of the remote webserver to use that info,
> > but as stated, it would probably be very easy to work around such
> > auth schemes.
> >
> > > Le Mercredi 22 Janvier 2003 14:27, vous avez écrit :
> > > > Laurent HENRY wrote:
> > > > > hi,
> > > > >
> > > > > i come back on an old topic i found in the archives of the mailing
> > > > > list, a thread named "Passthrough TCP/IP address".
> > > > > I'm facing exactly the same problem now and i don't know how to
> > > > > resolve it.
> > > > >
> > > > > Some of the client of my network need to connect to a website using
> > > > > an IP address access lists (for a paying subscription).
> > > > > My clients can't have Internet access without the proxy, so i can't
> > > > > give them direct access to the site and bypass the squid as told in
> > > > > the thread. The foreign webserver wants to see the IP of the client
> > > > > and only get the IP of my proxy, so they are refused.
> > > > > Can i configure the proxy to make something resolving the problem ?
> > > > >
> > > > > This case is very hard to understand for me because some client
> > > > > systems seems to actually pass through and some not;this without any
> > > > > action from me...
> > > >
> > > > Tell the remote server (service), to look at the X-Forwarded-for
> > > > field in the http request send by out.
> > > > Usage of this header is controlled in squid.conf.
> > > >
> > > > Anyway, we were faced with similar problems in the past : modern
> > > > webserver will use authentication based upon usernames/password etc.
> > > >
> > > > Why , because i a higher level application should use high level
> > > > authentication schemes (tell them that :-).
> > > >
> > > > IP in the current internet world is being hacked-around all the time,
> > > > NAT-ing , routers+NAT, Firewall-NAT , etc. can make in this world
> > > > that any ip address can 'represent' many hosts.
> > > >
> > > > So they are simply implementing poor auth. schemes,...
> > > >
> > > > M.

-- 
 'Time is a consequence of Matter thus
 General Relativity is a direct consequence of QM
 (M.E. Mar 2002)
Received on Wed Jan 22 2003 - 07:24:44 MST

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