hosts.equiv(5) — Linux manual page

NAME | DESCRIPTION | FILES | NOTES | EXAMPLES | SEE ALSO | COLOPHON

hosts.equiv(5)             File Formats Manual            hosts.equiv(5)

NAME         top

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

DESCRIPTION         top

       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         top

       /etc/hosts.equiv

NOTES         top

       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         top

       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         top

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

COLOPHON         top

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Linux man-pages 6.9.1          2024-05-02                 hosts.equiv(5)

Pages that refer to this page: pam_rhosts(8)