access.conf(5) — Linux manual page


ACCESS.CONF(5)                Linux-PAM Manual                ACCESS.CONF(5)

NAME         top

       access.conf - the login access control table file

DESCRIPTION         top

       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):


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

       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

       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         top

       These are some example lines which might be specified in

       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 :

       + : root :

       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 or

       + : root : 192.168.201.

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

       + : root :

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

       + : root :

       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

       + : @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

       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

SEE ALSO         top

       pam_access(8), pam.d(5), pam(8)

AUTHORS         top

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

       Network address / netmask description and example text was introduced
       by Mike Becher <>.

COLOPHON         top

       This page is part of the linux-pam (Pluggable Authentication Modules
       for Linux) project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, see ⟨//⟩.  This page was obtained from the
       tarball Linux-PAM-1.3.0.tar.bz2 fetched from
       ⟨⟩ on 2020-11-01.  If you discover
       any rendering problems in this HTML version of the page, or you be‐
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       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

Linux-PAM Manual                 04/01/2016                   ACCESS.CONF(5)

Pages that refer to this page: access.conf(5)pam_access(8)