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man pages section 8: System Administration Commands

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Updated: Wednesday, July 27, 2022

idmap_ad (8)


idmap_ad - Samba's idmap_ad Backend for Winbind


Please see following description for synopsis


System Administration tools                                        IDMAP_AD(8)

       idmap_ad - Samba's idmap_ad Backend for Winbind

       The idmap_ad plugin provides a way for Winbind to read id mappings from
       an AD server that uses RFC2307/SFU schema extensions. This module
       implements only the "idmap" API, and is READONLY. Mappings must be
       provided in advance by the administrator by adding the uidNumber
       attributes for users and gidNumber attributes for groups in the AD.
       Winbind will only map users that have a uidNumber and whose primary
       group have a gidNumber attribute set. It is however recommended that
       all groups in use have gidNumber attributes assigned, otherwise they
       are not working.

       Currently, the ad backend does not work as the default idmap backend,
       but one has to configure it separately for each domain for which one
       wants to use it, using disjoint ranges. One usually needs to configure
       a writeable default idmap range, using for example the tdb or ldap
       backend, in order to be able to map the BUILTIN sids and possibly other
       trusted domains. The writeable default config is also needed in order
       to be able to create group mappings. This catch-all default idmap
       configuration should have a range that is disjoint from any explicitly
       configured domain with idmap backend ad. See the example below.

       range = low - high
           Defines the available matching UID and GID range for which the
           backend is authoritative. Note that the range acts as a filter. If
           specified any UID or GID stored in AD that fall outside the range
           is ignored and the corresponding map is discarded. It is intended
           as a way to avoid accidental UID/GID overlaps between local and
           remotely defined IDs.

       schema_mode = <rfc2307 | sfu | sfu20>
           Defines the schema that idmap_ad should use when querying Active
           Directory regarding user and group information. This can be either
           the RFC2307 schema support included in Windows 2003 R2 or the
           Service for Unix (SFU) schema. For SFU 3.0 or 3.5 please choose
           "sfu", for SFU 2.0 please choose "sfu20". Please note that the
           behavior of primary group membership is controlled by the
           unix_primary_group option.

       unix_primary_group = yes/no
           Defines whether the user's primary group is fetched from the SFU
           attributes or the AD primary group. If set to yes the primary group
           membership is fetched from the LDAP attributes (gidNumber). If set
           to no the primary group membership is calculated via the
           "primaryGroupID" LDAP attribute.

           Default: no

       unix_nss_info = yes/no
           If set to yes winbind will retrieve the login shell and home
           directory from the LDAP attributes. If set to no or the AD LDAP
           entry lacks the SFU attributes the options template shell and
           template homedir are used.

           Default: no

       The following example shows how to retrieve idmappings from our
       principal and trusted AD domains. If trusted domains are present id
       conflicts must be resolved beforehand, there is no guarantee on the
       order conflicting mappings would be resolved at this point. This
       example also shows how to leave a small non conflicting range for local
       id allocation that may be used in internal backends like BUILTIN.

                workgroup = CORP

                idmap config * : backend = tdb
                idmap config * : range = 1000000-1999999

                idmap config CORP : backend  = ad
                idmap config CORP : range = 1000-999999

       The original Samba software and related utilities were created by
       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | service/network/samba |
       |Stability      | Volatile              |

       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at http://www.samba.org/.

Samba 4.13.17                     06/28/2022                       IDMAP_AD(8)