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:
[ + | - ] [hostname] [username]
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) preceeded 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 preceeding 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) preceeded by a plus (+) sign. You can also explicitly
deny access to a specific user by preceeding 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 preceeding the netgroup by an @ sign.
Be extremely careful when using the plus (+) sign. A simple typographical
error could result in a standalone plus sign. A standalone plus sign is
a wildcard character that means "any host"!