The hosts.equiv file allows or denies hosts and users to use the r-commands (e.g. rlogin, rsh or rcp) without supplying a password.
The file uses the following format:
The hostname is the name of a host which is logically equivalent to the local host. Users logged into that hosts are allowed to access like-named user accounts on the local host without supplying a password. The hostname may be (optionally) preceded by a plus (+) sign. If the plus sign is used alone it allows any host to access your system. You can expicitly deny access to a host by preceding the hostname by a minus (-) sign. Users from that host must always supply a password. For security reasons you should always use the FQDN of the hostname and not the short hostname.
The username entry grants a specific user access to all user accounts (except root) without supplying a password. That means the user is NOT restricted to like-named accounts. The username may be (optionally) preceded by a plus (+) sign. You can also explicitly deny access to a specific user by preceding the username by a minus (-) sign. This says that the user is not trusted no matter what other entries for that host exist.
Netgroups can be specified by preceding the netgroup by an @ sign.