Learning Red Hat Linux

Configuring a Dial-In Shell Server

A dial-in server lets you connect to a system via a modem and phone line, and obtain a shell prompt, from which you can issue commands and view output. Using a dial-in server is a great deal like using Telnet or a secure shell server, except that your connection to the server is via a phone line. The mgetty package provides a simple-to-use dial-in server.

Configuration

To configure mgetty to answer incoming modem calls, use your favorite text editor to find the following lines in the file /etc/inittab:

# Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6

Then, add the following line after the last of these lines:

7:2345:respawn:/sbin/mgetty modem

Notice that the added line invokes mgetty, not mingetty. The final argument specified on the added line assumes that your modem is configured as /dev/modem. If your modem is configured as a different device, you must adjust the added line accordingly. The Chapter 11 described the use of modemtool to configure your modem; if you followed its instructions, /dev/modem refers to your modem.

To cause your configuration change to take effect, you must reboot your system. Alternatively, you can cause the init process to re-examine the inittab file. To do so, issue the following command:

/sbin/telinit q

The mgetty