Frequently, systems are known by one name for DNS purposes and another for UUCP purposes. UUCPNAME permits you to define a different hostname that appears in the headers of outgoing UUCP mail.
UUCPNODES defines the commands that return a list of hostnames for the systems we are connected directly to via UUCP connections.
BANGIMPLIESUUCP and BANGONLYUUCP ensure that mail addressed with UUCP `bang' syntax is treated according to UUCP behavior rather than the more current Domain Name Service behavior used today on Internet.