Re: Global proxy autoconfig script?

From: Peter Marelas <>
Date: Thu, 11 Sep 1997 00:01:15 +1000 (EST)

On Wed, 10 Sep 1997, Oskar Pearson wrote:

> Hi
> We were talking about a global web server that would run a script, and
> based on the IP address of the client machine, return a different
> java auto-config script.
> > >Perhaps his would be good as a sub-routine to each ISP own auto-config
> > >file, but is this scalable ? Autooconfig is nothing but a java script,
> > >interpreted for EACH object. Is this is BIG, it will be SLOW...
> >
> > The Proxy Auto Configuration (PAC) script could be generated by a Perl
> We have a related problem:
> We have numerous branches spread around the country. We would like to
> get a machine in each of those branches to handle traffic for their
> area, so that connections don't come all the way over our national
> links to get to the cache up here. It would, however, be nice to
> not have 1 different config file for each branch (ie settings would be
> perfectly uniform) I spent a long time sitting and thinking about this,
> and decided that there are basically 4 options:
> 1) A central auto-config script that runs a CGI on our machines and
> decides where they are supposed to go based on the request.
> 2) We add local routes (local to each branch) that point to
> a different cache machine... yucky
> 3) We modify bind so that it responds with a different IP address
> for an A record request based on the address the request came from.
> 4) Change the way netscape and Explorer work.
> I think that 4 is the best option, but it's going to be difficult
> (we would need an rfc or something). Here is my idea as to how they would work:
> In the reverse DNS ( we add an A record that
> points to a 'config-server'. (anyone thought of that before?)
> so you have
> cacheconfig A
> in the reverse zone. Your proxy client then says
> "gethostbyname(" and connects
> to that machine. It then attempts to connect to that machine using (either
> http or a 'cache-config-specific' variant) and asks for a java auto-config
> file...
> I dig the idea... if you are allowed A records in PTR zones I haven't
> tried, but I don't see why you shouldn't be able to have it...
> Of course, there might be something in the Internet drafts about auto-config
> systems that have been released (I haven't had a chance to look at them,
> but look at "ACAP -- Application Configuration Access Protocol",
> draft-ietf-acap-spec-06.txt). Perhaps these ideas could be integrated...
> So if someone changes IP addresses by dialing up in the UK, it will
> talk to that service providers' cache....

Hmm..a simpler approach..

Use a squid system with 2 IP addresses.

One IP address being private. Maybe
The other being internet connected.

Client browsers access

This is what I would do for many services if I were to design a national
or international ISP.

Peter Marelas

Phase One Interactive - Sun Solaris/Unix/Networking Consultant
P.O Box 549, Templestowe 3106 Melbourne, Australia
Received on Wed Sep 10 1997 - 07:14:59 MDT

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