ACCESS.CONF(5)            (06/08/2020)             ACCESS.CONF(5)

     NAME
          access.conf - the login access control table file

     DESCRIPTION
          The /etc/security/access.conf file specifies (user/group,
          host), (user/group, network/netmask), (user/group, tty),
          (user/group, X-$DISPLAY-value), or (user/group,
          pam-service-name) combinations for which a login will be
          either accepted or refused.

          When someone logs in, the file access.conf is scanned for
          the first entry that matches the (user/group, host) or
          (user/group, network/netmask) combination, or, in case of
          non-networked logins, the first entry that matches the
          (user/group, tty) combination, or in the case of
          non-networked logins without a tty, the first entry that
          matches the (user/group, X-$DISPLAY-value) or (user/group,
          pam-service-name/) combination. The permissions field of
          that table entry determines whether the login will be
          accepted or refused.

          Each line of the login access control table has three fields
          separated by a ":" character (colon):

          permission:users/groups:origins

          The first field, the permission field, can be either a "+"
          character (plus) for access granted or a "-" character
          (minus) for access denied.

          The second field, the users/group field, should be a list of
          one or more login names, group names, or ALL (which always
          matches). To differentiate user entries from group entries,
          group entries should be written with brackets, e.g.
          (group).

          The third field, the origins field, should be a list of one
          or more tty names (for non-networked logins), X $DISPLAY
          values or PAM service names (for non-networked logins
          without a tty), host names, domain names (begin with "."),
          host addresses, internet network numbers (end with "."),
          internet network addresses with network mask (where network
          mask can be a decimal number or an internet address also),
          ALL (which always matches) or LOCAL. The LOCAL keyword
          matches if and only if pam_get_item(3), when called with an
          item_type of PAM_RHOST, returns NULL or an empty string (and
          therefore the origins field is compared against the return
          value of pam_get_item(3) called with an item_type of PAM_TTY
          or, absent that, PAM_SERVICE).

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          If supported by the system you can use @netgroupname in host
          or user patterns. The @@netgroupname syntax is supported in
          the user pattern only and it makes the local system hostname
          to be passed to the netgroup match call in addition to the
          user name. This might not work correctly on some libc
          implementations causing the match to always fail.

          The EXCEPT operator makes it possible to write very compact
          rules.

          If the nodefgroup is not set, the group file is searched
          when a name does not match that of the logged-in user. Only
          groups are matched in which users are explicitly listed.
          However the PAM module does not look at the primary group id
          of a user.

          The "#" character at start of line (no space at front) can
          be used to mark this line as a comment line.

     EXAMPLES
          These are some example lines which might be specified in
          /etc/security/access.conf.

          User root should be allowed to get access via cron, X11
          terminal :0, tty1, ..., tty5, tty6.

          +:root:crond :0 tty1 tty2 tty3 tty4 tty5 tty6

          User root should be allowed to get access from hosts which
          own the IPv4 addresses. This does not mean that the
          connection have to be a IPv4 one, a IPv6 connection from a
          host with one of this IPv4 addresses does work, too.

          +:root:192.168.200.1 192.168.200.4 192.168.200.9

          +:root:127.0.0.1

          User root should get access from network 192.168.201.  where
          the term will be evaluated by string matching. But it might
          be better to use network/netmask instead. The same meaning
          of 192.168.201.  is 192.168.201.0/24 or
          192.168.201.0/255.255.255.0.

          +:root:192.168.201.

          User root should be able to have access from hosts
          foo1.bar.org and foo2.bar.org (uses string matching also).

          +:root:foo1.bar.org foo2.bar.org

          User root should be able to have access from domain
          foo.bar.org (uses string matching also).

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          +:root:.foo.bar.org

          User root should be denied to get access from all other
          sources.

          -:root:ALL

          User foo and members of netgroup admins should be allowed to
          get access from all sources. This will only work if netgroup
          service is available.

          +:@admins foo:ALL

          User john and foo should get access from IPv6 host address.

          +:john foo:2001:db8:0:101::1

          User john should get access from IPv6 net/mask.

          +:john:2001:db8:0:101::/64

          Members of group wheel should be allowed to get access from
          all sources.

          +:(wheel):ALL

          Disallow console logins to all but the shutdown, sync and
          all other accounts, which are a member of the wheel group.

          -:ALL EXCEPT (wheel) shutdown sync:LOCAL

          All other users should be denied to get access from all
          sources.

          -:ALL:ALL

     NOTES
          The default separators of list items in a field are space,
          ',', and tabulator characters. Thus conveniently if spaces
          are put at the beginning and the end of the fields they are
          ignored. However if the list separator is changed with the
          listsep option, the spaces will become part of the actual
          item and the line will be most probably ignored. For this
          reason, it is not recommended to put spaces around the ':'
          characters.

     SEE ALSO
          pam_access(8), pam.d(5), pam(7)

     AUTHORS
          Original login.access(5) manual was provided by Guido van
          Rooij which was renamed to access.conf(5) to reflect

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          relation to default config file.

          Network address / netmask description and example text was
          introduced by Mike Becher <mike.becher@lrz-muenchen.de>.

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