Книга: Linux Network Administrator Guide, Second Edition

What UUCP Needs to Know

What UUCP Needs to Know

Before you start writing the UUCP configuration files, you have to gather some information that UUCP requires.

First, you have to figure out what serial device your modem is attached to. Usually, the (DOS) ports COM1: through COM4: map to the device special files /dev/ttyS0 through /dev/ttyS3. Some distributions, such as Slackware, create a link called /dev/modem to the appropriate ttyS* device file, and configure kermit, seyon, and any other communication programs to use this generic file. In this case, you should use /dev/modem in your UUCP configuration, too.

The reason for using a symbolic link is that all dial-out programs use so-called lock files to signal when a serial port is in use. The names of these lock files are a concatenation of the string LCK… and the device filename, for instance LCK…ttyS1. If programs use different names for the same device, they will fail to recognize each other's lock files. As a consequence, they will disrupt each other's session when started at the same time. This is quite possible when you schedule your UUCP calls using a crontab entry. For details on serial port setup, please refer to Chapter 4, Configuring the Serial Hardware.

Next, you must find out at what speed your modem and Linux will communicate. You have to set this speed to the maximum effective transfer rate you expect to get. The effective transfer rate may be much higher than the raw physical transfer rate your modem is capable of. For instance, many modems send and receive data at 56 kbps. Using compression protocols such as V.42bis, the actual transfer rate may climb over 100 kbps.

Of course, if UUCP is to do anything at all, you need the phone number of a system to call. Also, you need a valid login ID and possibly a password for the remote machine.[91]

You also have to know exactly how to log into the system. Do you have to press the Enter key before the login prompt appears? Does it display login: or user:? This is necessary for composing the chat script. If you don't know, or if the usual chat script fails, try to call the system with a terminal program like kermit or minicom and record exactly what you have to do.

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