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.
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 : 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
+ : @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
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 <email@example.com>.
This page is part of the linux-pam (Pluggable Authentication Modules
for Linux) project. Information about the project can be found at
⟨https://fedorahosted.org/linux-pam/⟩. If you have a bug report for
this manual page, see ⟨https://fedorahosted.org/linux-pam/report⟩.
This page was obtained from the tarball Linux-PAM-1.3.0.tar.gz
fetched from ⟨http://www.linux-pam.org/library/⟩ on 2017-03-13. If
you discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page), send a
mail to firstname.lastname@example.org
Linux-PAM Manual 04/01/2016 ACCESS.CONF(5)