hosts.equiv

HOSTS.EQUIV(5)              Linux Programmer's Manual             HOSTS.EQUIV(5)



NAME
       hosts.equiv - list of hosts and users that are granted "trusted" r
       command access to your system

DESCRIPTION
       The file /etc/hosts.equiv 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|+@netgroup|-@netgroup [+|[-]username|+@netgroup|-@netgroup]

       The hostname is the name of a host which is logically equivalent to the
       local host.  Users logged into that host 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
       explicitly deny access to a host by preceding the hostname by a minus (-)
       sign.  Users from that host must always supply additional credentials,
       including possibly 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 with 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.

       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"!

FILES
       /etc/hosts.equiv

NOTES
       Some systems will honor the contents of this file only when it has owner
       root and no write permission for anybody else.  Some exceptionally
       paranoid systems even require that there be no other hard links to the
       file.

       Modern systems use the Pluggable Authentication Modules library (PAM).
       With PAM a standalone plus sign is considered a wildcard character which
       means "any host" only when the word promiscuous is added to the auth
       component line in your PAM file for the particular service (e.g.,
       rlogin).

EXAMPLES
       Below are some example /etc/host.equiv or ~/.rhosts files.

       Allow any user to log in from any host:

           +

       Allow any user from host with a matching local account to log in:

           host

       Note: the use of +host is never a valid syntax, including attempting to
       specify that any user from the host is allowed.

       Allow any user from host to log in:

           host +

       Note: this is distinct from the previous example since it does not
       require a matching local account.

       Allow user from host to log in as any non-root user:

           host user

       Allow all users with matching local accounts from host to log in except
       for baduser:

           host -baduser
           host

       Deny all users from host:

           -host

       Note: the use of -host -user is never a valid syntax, including
       attempting to specify that a particular user from the host is not
       trusted.

       Allow all users with matching local accounts on all hosts in a netgroup:

           +@netgroup

       Disallow all users on all hosts in a netgroup:

           -@netgroup

       Allow all users in a netgroup to log in from host as any non-root user:

           host +@netgroup

       Allow all users with matching local accounts on all hosts in a netgroup
       except baduser:

           +@netgroup -baduser
           +@netgroup

       Note: the deny statements must always precede the allow statements
       because the file is processed sequentially until the first matching rule
       is found.

SEE ALSO
       rhosts(5), rlogind(8), rshd(8)

COLOPHON
       This page is part of release 5.13 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



Linux                              2020-06-09                     HOSTS.EQUIV(5)