The UUCP communications network

A UUCP network consists of a number of systems that exchange information. Each system has a working copy of UUCP and a unique name that identifies it in the network. There is no central control system for a UUCP network; each system controls its own connections. In a UUCP network, computers connect computers in the same building or to networks that include computers around the world.

In a UUCP network, every system (also known as a site) communicates with at least one other system, but does not have to call all the sites. See Figure 1 for a diagram of a simple network. This network has four sites named North, South, East, and West.

Figure 1. A simple UUCP network What a simple UUCP network looks like.

The lines indicate a direct connection between two systems:

North: Connects to East, South, West
East: Connects to North, South
South: Connects to North, East
West: Connects to North

Each system exchanges files with the systems it calls directly. Users on North can send files directly to any of the other three systems, but users on West can only send files directly to North. These are called direct connections to distinguish them from connections made through intermediaries. Someone on West can send a file to someone on East indirectly through North, if North has agreed to pass along file requests from West to East. This makes North an intermediary node.

Alternatively, North could set up its configuration so that West could not transfer files through North, but only to North. This is called a terminal or leaf-node connection. For information on how to define a connection between two nodes, see the description of the COMMANDS option in The Permissions file.