Go to main content

man pages section 8: System Administration Commands

Exit Print View

Updated: Wednesday, July 27, 2022

idmap_rid (8)


idmap_rid - Samba's idmap_rid Backend for Winbind


Please see following description for synopsis


System Administration tools                                       IDMAP_RID(8)

       idmap_rid - Samba's idmap_rid Backend for Winbind

       The idmap_rid backend provides a way to use an algorithmic mapping
       scheme to map UIDs/GIDs and SIDs. No database is required in this case
       as the mapping is deterministic.

       Currently, there should to be an explicit idmap configuration for each
       domain that should use the idmap_rid backend, using disjoint ranges.

       NOTE: The idmap_rid backend can NOT bet used as the default backend.
       One usually needs to define a writeable default idmap range, using a
       backend like tdb or ldap that can create unix ids, in order to be able
       to map the BUILTIN sids and other domains, and also in order to be able
       to create group mappings. 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
           algorithmically determined UID or GID fall outside the range, they
           are 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.

       base_rid = INTEGER
           Defines the base integer used to build SIDs out of a UID or a GID,
           and to rebase the UID or GID to be obtained from a SID. This means
           SIDs with a RID less than the base rid are filtered. The default is
           not to restrict the allowed rids at all, i.e. a base_rid value of

           Use of this parameter is deprecated.

       The Unix ID for a RID is calculated this way:

                          ID = RID - BASE_RID + LOW_RANGE_ID.

       Correspondingly, the formula for calculating the RID for a given Unix
       ID is this:

                          RID = ID + BASE_RID - LOW_RANGE_ID.

       This example shows how to configure two domains with idmap_rid, the
       principal domain and a trusted domain, leaving the default id mapping
       scheme at tdb. The example also demonstrates the use of the base_rid
       parameter for the trusted domain.

                security = domain
                workgroup = MAIN

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

                idmap config MAIN : backend     = rid
                idmap config MAIN : range       = 10000 - 49999

                idmap config TRUSTED : backend  = rid
                idmap config TRUSTED : range    = 50000 - 99999

       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_RID(8)