There are three main versions of UUCP:
HoneyDanBer UUCP (HDB/BNU)
Version 2 UUCP was written in 1977 by Mike Lesk, David Nowitz, and Greg Chesson at AT&T Bell Laboratories. (Version 2 was a rewrite of the first UUCP version, which was written by Lesk the previous year and was never released outside AT&T.) Version 2 was distributed with UNIX Version 7 in 1977, and is at the heart of many vendors' older versions of UUCP. The Berkeley versions of UUCP are derived largely from Version 2, and include many enhancements.
Version 2 UUCP is seldom seen anymore. It has largely been replaced by HDB UUCP at sites still using UUCP. We describe it in this chapter for historical reasons and to be complete. However, we encourage you to think about upgrading to the HDB form, if possible.
In 1983, AT&T researchers Peter Honeyman, David A. Nowitz, and Brian E. Redman developed a new version of UUCP that became known as HoneyDanBer UUCP. AT&T began distributing this version with UNIX System V Release 3 under the name " Basic Networking Utilities," or BNU. The BNU version is probably the most commonly used version of UUCP today.
From the system administrator's point of view, the primary difference between these two versions of UUCP is their configuration files. Version 2 uses one set of configuration files, while BNU has another. Look in the /usr/lib/uucp directory (on some systems, the directory is renamed /etc/uucp). If you have a file called USERFILE, you are using Version 2 configuration files, and probably have Version 2 UUCP. If you have a file called Permissions, you are using BNU configuration files, and probably have BNU.
Another significant difference between the two versions is the support for security options and enhanced logging. BNU is much improved over Version 2 in both regards. We describe the configuration differences later, and present the logging for BNU in "UUCP Log Files" in Chapter 10.
Taylor UUCP is a version of UUCP written by Ian Lance Taylor. It is a free version of UUCP which is covered under the GNU Public License. It supports either style of configuration files, and will even allow you to use both at the same time. Taylor UUCP is frequently distributed with the Linux operating system. Most Linux distributions use the BNU-style configuration files.
In addition to Taylor UUCP, several free or inexpensive implementations of UUCP are available for UNIX, DOS, MacOS, AmigaOS, and other systems - even VMS! Because these implementations are not widely used, documentation on them is limited and their security aspects are unknown (at least to us). Whatever version you are using, we expect that many of our comments in the remainder of this chapter apply to it.