The Linux Documentation Project at www.tldp.org/ offers many in-depth resources for configuring and troubleshooting these connections. Google is also an invaluable tool for dealing with specific questions about these connections. For many other useful references, see the “References” section at the end of this chapter.
Here are a few troubleshooting tips culled from many years of experience:
If your modem connects and then hangs up, you are probably using the wrong password or dialing the wrong number. If the password and phone number are correct, it is likely an authentication protocol problem.
If you get ...