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UUCP (Unix to Unix CoPy) is used for transferring files from one system to another. The copy may result in other work being done on one of the systems, such as invoking mail or news programs, which is discussed later in this chapter. Basically, UUCP is a collection of programs that are capable of the following:
- • Transferring files between Unix systems
- • Executing commands on remote systems
Although UUCP is not in as widespread use as TCP/IP, it is still available on your system. Without knowledge of this, it is possible for the experienced hacker to access your files using UUCP. It is shipped with standard logins and permissions established. This chapter presents what UUCP is, how it works, and how to configure it correctly.
Unlike many other networking environments, UUCP requires no special hardware. Its simplicity is due in part to its age: UUCP formed the basis for communication on USENET and early networks. The first network many Unix people worked on was a collection of XENIX and Unix machines joined together with serial cables and UUCP. Although various protocols can be run on LANs (local area networks), UUCP has traditionally been used in long haul dial-up networks. That is, call the remote machine when there is something for it; otherwise, UUCP does nothing.
UUCP has been used in many different situations. Large financial organizations, for example, used it to send daily processing information to a central computer; sales and distribution companies used UUCP to send inventory and pricing information to remote offices. Although UUCP made these transfers simple, this type of networking still involved cooperation between system administrators.
Two versions of UUCP are currently being shipped. The first UUCP was written by Mike Lesk of AT&T as a research project. During and after the project, UUCP became such a success that Mike joined with David Nowitz and Greg Chesson to build the version of UUCP that was shipped with Version 7 Unix, and subsequently became known as Version 2 UUCP. This version is still shipped by some vendors, and many older Unix systems have this version.
With the release of System V Release 3 from AT&T, a new UUCP version was released that was known by a number of names, most notably the Basic Networking Utilities, or HoneyDanBer (HDB) UUCP. HDB UUCP was written in 1983 by Peter Honeyman, David A. Nowitz, and Brian E. Redman. They named this version after the login names they used on the system (Honey, Dan, Ber). HDB provides additional capabilities, such as newer modem and network support, and corrects design deficiencies of Version 2.
For the most part, communication between different UUCP versions is transparent after they have been configured. Although many of the features have not changed, the names and layouts of many of the configuration files have changed. As a result, it is easy to tell which version you have. If you see a file named L.sys in the directory /usr/lib/uucp, you have Version 2. A file named Systems in this directory is only found on HoneyDanBer UUCP. No /usr/lib/uucp directory means that you don’t have UUCP installed. Table 3.1 shows a list of the file names that make up each version, and their use.
| Version 2 Files | BNU/HDB Files | Description |
|---|---|---|
| L-devices | Devices | Contains a description of the devices that are attached to your system. |
| L-dialcodes | Dialcodes | Uses text to designate areas instead of the actual area codes. This file describes that text. |
| Dialers | Contains the commands needed to get a modem or other device to make a call. | |
| Maxuuscheds | Contains a number that is the maximum number of uuscheds that can be running at one time. | |
| Maxuuxqts | The same as Maxuuscheds, but it is for uuxqt. | |
| USERFILE | Permissions | Contains the needed information to control the security of your machine. |
| Poll | You can elect to call sites at specific times, which is polling. This file describes who is called, and when. | |
| Sysfiles | Used to configure separate Systems files for cu and uucico. | |
| L.sys | Systems | Contains the list of systems you can call, or that you know about, and how to contact them. It contains phone numbers, user names, and passwords. |
| Uutry | Shell command to test chat scripts by calling the remote system. | |
| remote.unknown | Shell command to record calls from unknown systems. | |
| uucheck | Checks the UUCP directories and Permissions file for proper setup and consistency. | |
| uucico | uucico | The UUCICO program. This is the heart of the UUCP system. |
| uuclean | uucleanup | General clean-up tool. |
| uudemon.admin | Shell command to send UUCP status information to the system administrator. | |
| uudemon.cleanu | Shell command to do general UUCP system cleanup tasks. | |
| uudemon.hour | Shell command to run the UUCP scheduler. | |
| uudemon.poll | Shell command to call (or poll) the specified systems at the designated hours (see Poll). | |
| uudemon.day | UUCP maintenance tasks to be run once per day. | |
| uudemon.kr | Runs uucico once per hour and processes all pending work. | |
| uudemon.wk | UUCP maintenance tasks to be performed once per week. | |
| uugetty | Alternate getty program. | |
| uusched | The uucp scheduler. | |
| uutry | A debugging program. | |
| uusub | Defines a UUCP sub-network and monitors the traffic between the hosts. | |
| uuxqt | uuxqt | Executes jobs on your system that are required as part of the transfer. |
| SEQF | The sequence number for the next job. | |
| L_stat | System status file. | |
| L_sub | UUCP connection statistics. | |
| R_stat | Request status file. | |
| R_sub | UUCP traffic statistics. | |
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