For clusters of machines with many users (as might be the case in a university or large industrial environment), an intermediate server might be used. This intermediate or "slave" server runs on each computer system, and is responsible for mediating news reading requests and performing local caching of recently-retrieved news articles.
Typically, a client attempting to obtain news service would first attempt to connect to the news service port on the local machine. If this attempt were unsuccessful, indicating a failed server, an installation might choose to either deny news access, or to permit connection to the central "master" news server.
For workstations or other small systems, direct connection to the master server would probably be the normal manner of operation.
This specification does not cover the operation of slave NNTP servers. We merely suggest that slave servers are a logical addition to NNTP server usage which would enhance operation on large local area networks.