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
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
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
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 0.
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
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
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.