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).

       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).

       +: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 relation to default config file.

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

Linux-PAM Manual                                   06/08/2020                                     ACCESS.CONF(5)