ppp

Getting a serial modem to connect to your ISP using ppp.

First, you must have installed pp support.  If not, you will need to get and install the ppp RPM for RedHat. It is included on your distribution CD. Think of them as packaged zip or tar files. The command used to install them is 'rpm -i filename.rpm'. Do a man rpm for more information.

Now that you have ppp installed, you are a few keystrokes from getting it to work. First, a simple command line string to get you going.....this is all one line. Substitute 5551212 with your ISP dial-up number, username with your account name and password with your password. You can execute it at the command line or build it into a script file....

pppd connect 'chat -v "" ATDT5551212 CONNECT "" ogin: username word: password' /dev/ttyS0 57600 debug persist crtscts modem defaultroute

/dev/ttyS0 is serial port1. You could also use cua0.
/dev/ttyS1 is serial port2. You could also use cua1.

The 'persist' keeps the line up if it is dropped, it redials automatically

Now - to use the 'correct' scripts that come with ppp....

cp /usr/src/ppp-x.x.x/scripts/* /etc/ppp/

Included in the pre-made scripts are ppp-on and ppp-off. If you edit ppp-on, you will see places to insert your ISP dial-up number, username and password. Once you have made those changes, you can now execute the following commands:

cd /etc/ppp ; ./ppp-on ; ./ppp-off

Your modem should dial up and connect. Try pinging your ISP webserver. If it times out, try using a known IP address.  If that doesn't work, it is possible your modem is still trying to connect.

You can now manually execute these scripts when you want to connect to the Internet. 

pppd has recently changed to include features such as demand dialing (like diald gave us) and complete pap and chap authentication.  When upgrading my systems to the 2.2.16 kernel, I had a bit of trouble getting pppd to work.  The answer was in the syslog - it was trying to use reverse authentication by default.  I edited /etc/ppp/options and added 'noauth' to the file and diald brought the link up like magic ;-)

To automatically connect when traffic is sensed, check out diald. And don't forget to protect your system with a good firewall!