Re: Transparent caching

From: Daniel O'Callaghan <>
Date: Thu, 19 Dec 1996 09:05:56 +1100 (EST)

On Wed, 18 Dec 1996, Paul M. Hoogsteder wrote:

> Does anyone know transparent-cache implementations in software, or is
> anyone working on something like that? (Other than the Interceptor).
> 75% of our network-traffic goes to personal users who dialin with PPP, of
> which probably 90% is either ftp or http. Setting up a transparent cache
> can save us thousands of dollars every month (at $0.30 USD for every
> megabyte).

Actually, it is possible to develop something like this. It depends on
how good you are at kernel hacking. Darren Reed's ipfilter/ipnat software
<> can redirect all requests to any
address on a given port (e.g. 80) to a different port/host. Somehow, I
have not looked at the details, the original destination host is
transmitted to the proxy, via a library of routines which Darren supplies
as source code.

It would thus be possible to set up the following:

--------80->ipnat---8888->Redirector-------> Squid

The ipnat code sends *all* requests for host:80 to port 8888, where the
Redirector program reads the request from the client, and converts it to
a proxy request which it passes to Squid.

Ipfilter/ipnat runs on Free/Net/OpenBSD, SunOS4.x, Solaris.

Since an example Redirector program, and a working transparent FTP proxy
are supplied in the IPfilter srcs, it might not be too difficult to
implement an http version.


Received on Wed Dec 18 1996 - 14:17:37 MST

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