etchosts.equiv

/etc/hosts.equiv

This file is used by the various "r" protocols, such as rcp(1) and rlogin(1). They are a relic of an earlier age, when Internet security was not so great a concern, and should not be used today. There should be no uncommented entry in this file unless you specifically put it there. If you're really interested in this, check out hosts.equiv(5), rshd(8), and rlogind(8).