So recently Verizon has stopped letting me do free tethering and I've been looking for a replacement. Apparently all of the free ISPs I can find all require that you use their shitty Windows program to connect, so I decided, "I have a phone line, a modem and an internet connection, maybe I can make my own ISP".
Basically, I want to take a computer with a dialup modem and an ethernet connection to a cable modem and make it so whenever someone calls, the computer picks up and acts like an ISP (requests username/password, then forwards all requests to the cable modem).
Obviously, it wouldn't be that great (added latency, phone line won't work while it's active), but it's at least theoretically possible. I'm just wondering if there's software designed to do it.
pppd will do it, you can read http://www.tldp.org/HOWTO/PPP-HOWTO/ or similar generally you'll need to know routing and networking, pppd options and chat options. Then you need to set pppd/chat (pppd starts chat to control the modem) to wait for a RING, answer the modem, then pppd takes over and establishes the ppp session. -- damjan