I am in the process of building a dial up simulator involving a 1990s era desktop and laptop. The desktop, which is connected to Ethernet, acts as the dial-up server and the laptop computer dials in to the “server” through its built in modem. The connection is made through a Teltone telephone line simulator.

I downloaded a “vintage proxy” from GitHub in which typing in a url (ex:aol.com) will return that page from a year in the past using the Wayback Machine. This proxy will be running on a modern third computer.

My question is how the dial-up connected laptop can access the proxy server on the modern computer through the dial-up. I know that if I use a wireless router, I can access the proxy using the server’s IP address, but I don’t know how to do this through the simulated dial up connection, since the modern computer is connected to wifi, not through the simulated dial up connection.

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    What happens after you establish your dial up connection? Do you have a TCP Stack establish a PPP connection between the 2 computers? Assuming that's the case, you could put the proxy server in your IE/Firefox/etc server's settings OR run a transparent proxy on the server that automatically redirects all HTTP traffic. – Kelvin Sherlock Jul 14 '20 at 2:49
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    @raffzahn They are not modern machines. The only modern machine is the one with the proxy server. The other two computers are late 1990s models – user18789 Jul 14 '20 at 11:03
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    I’m voting to close this question because it is asking how to configure a modern system to simulate a retrocomputing experience. – another-dave Jul 14 '20 at 16:32
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    I disagree with the vote to close. This project would have benefit to someone with a retrocomputer with a modem. It seems more within the scope of restoration or use, rather than simulation. We accept questions like "How can I connect this system to my HDMI monitor?" after all. – RETRAC Jul 14 '20 at 20:14
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    It sounds like all you need to bridge connections on the modern computer so that traffic is rerouted to the loop back address. That is a simple networking question, not a good fit for this site. – Mark Williams Jul 15 '20 at 17:35

Assuming that you already have IP forwarding working through your dial-up host, there are two ways to direct a dial-up user to a specific proxy that I can think of:

  1. Configure the web browser on the system using dial-up to use the proxy.

  2. Reroute all web requests from the system using dial-up to the proxy.

If you are using a Windows system as the dial-up server, you are probably better off using option #1. option #2 is likely to be difficult.

If you are using a Linux/Unix system as the dial-up server, both options work. Option #2 in particular could be done using features like "iptables" or "pf". iptables is typically found on Linux systems, and pf is normally seen on BSD or BSD-derived systems (e.g. OpenBSD, pfSense, etc.) The specific configuration needed in iptables, pf, or other such tools, is outside the scope of this RetroComputing StackExchange site but information about those tools is readily available on the Internet.

If you do not already have your dial-up host forwarding IP traffic you'll need to set that up as well; setting up the host as a SLIP or PPP server would be a good approach. Specific procedures on that are also probably outside the scope of RetroComputing.

  • the search phrase is 'transparent proxy' – hildred Jul 18 '20 at 0:52

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