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This document is copyright © 2001 Jim Brooks.
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A first step is to add the numeric IP address of your ISP's DNS server to /etc/resolv.conf:
nameserver 10.20.30.40
This won't interfere with your local network if it is using static IP addresses.
The next step is to discover the prompts from your ISP dialup server.
(These prompts require answers from a "chat" script, see next step).
One way is to call your ISP dialup server using a textual communications program
such as minicom or Windows's Hyperterminal.
Typically, a ISP dialup server prompts for a username/password, then the desired protocol (PPP).
For example:
login: myusername password: mypwd protocol: ppp
BTW, persistent "LCP timeout" or "[LCP ConfRequest]" error messages can be caused by chat failing to correctly respond to the prompts. If that happens, then the dialup server never initiates PPP.
Formulate a "chat" script that will reply to each dialup prompt.
Each prompt/answer pair in a chat script is separated by spaces
For example:
#!/bin/sh pppd -detach connect 'chat -s -v "" ATDTnnn-nnnn CONNECT "" login: myusername password: mypwd protocol ppp' /dev/modem 115200 debug crtscts modem defaultroute
This script will call the dialup server and will try to establish a PPP connection.
/dev/modem is a symlink to the serial port #0 at /dev/cua0.
Hopefully, PPP on Linux is now working.