Database web hosting - What UUCP Needs to Know Before you start
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 Slack- ware, 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 kermitor minicom and record exactly what you have to do. Site Naming As with TCP/IP-based networking, your host has to have a name for UUCP networking. As long as you simply want to use UUCP for file transfers to or from sites you dial up directly, or on a local network, this name does not have to meet any standards.92 However, if you use UUCP for a mail or news link, you should think about having the name registered with the UUCP Mapping Project.93 The UUCP Mapping Project is described in Chapter 17, Electronic Mail. Even if you participate in a domain, you might consider having an official UUCP name for your site. Frequently, people choose their UUCP name to match the first component of their fully qualified domain name. Suppose your site’s domain address is swim.twobirds.com; then your UUCP hostname would be swim. Think of UUCP sites as knowing each other on a first-name basis. Of course, you can also use a UUCP name completely unrelated to your fully qualified domain name. However, make sure not to use the unqualified site name in mail addresses unless you have registered it as your official UUCP name. At the very best, mail to an unregistered UUCP host will vanish in some big black bit bucket. If you use a name already held by some other site, this mail will be routed to that site and cause its postmaster a lot of headaches. By default, the UUCP suite uses the name set by hostname as the site’s UUCP name. This name is commonly set by a command on the boot time rc scripts, and is usually stored in the /etc/hostname. If your UUCP name is different from what you set your hostname to, you have to use the hostname option in the config file to tell uucico about your UUCP name. This is described next. 91 If you’re just going to try out UUCP, get the number of an archive site near you. Write down the login and password — they’re public to make anonymous downloads possible. In most cases, they’re something like uucp/uucp or nuucp/uucp. 92 The only limitation is that it shouldn’t be longer than seven characters, so as to not confuse UUCP implementations that run on an operating system that imposes a narrow limit on filenames. Names that are longer than seven characters are often truncated by UUCP. Some versions even limit the name to six characters. 93 The UUCP Mapping Project registers all UUCP hostnames worldwide and makes sure they are unique.