Re: Transparent proxying issues.

From: Gilles Melanson <>
Date: Wed, 28 Jan 1998 18:28:19 -0500 (EST)

> Gilles Melanson <> wrote:
> |> I've asked the same and was poletly sent to read the FAQ, section 5 is
> |> entirely about transparent proxy and explains how to do that with a
> |> Cisco as a router and (also) Linux as a Squid platform (together with
> |> other environments).

> What happens when you try a simple "telnet somehost 80"? Try putting
> some simple "echo Hi there" server via inetd.conf on the squid machine
> and see if you get it. If you don't get it then the problem must with
> the the router original route mapping. If you do get it then try to
> connect to port 80 in the outside world from the proxy machine and see
> what happens (all these tests should be done with squid out of the
> game, of course).

By telnetting to port 80, it comes up with:

Trying x.x.x.x... (some IP other than the squidbox)

.. and it hangs. The route-map access-list is being hit, though, so the
router is lobbing requests off to the squidhost in some manner. IOS 11.2
and not 11.1, but I can't see there being much difference in the way they
handle the request. I can telnet to the squidhost port 80 w/o any
problems (to be expected). It is possible that it's not working because
of the outside host trying to come back in.. I mean, if the destination
port is 80 (coming back), it would likely hit the route-map as well. How
does Squid handle this..? Does it know to redirect the request back to
the client.. and how does the router handle it? That could be the problem
right there.

I'm at a loss, but I'd still like to beat my head against it some more if
anyone has any suggestions (if they've got it set up in a Cisco+Squid


Gilles Melanson                 ViaNet Internet Solutions NOC 
System/Network Administrator    128 Larch St., Sudbury, ON, Can P3E 5J8             Phone#: (705) 675-0400  ICQ UIN 1944562
Received on Wed Jan 28 1998 - 15:43:11 MST

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