Idmap config autorid

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Revision as of 21:31, 23 February 2019 by Hortimech (talk | contribs) (/* remove default domain)


The autorid back end works similar to the rid ID mapping back end, but can automatically assign IDs for different domains. This enables you to use the autorid back end:

  • For the SAMDOM domain and additional domains, without the need to create ID mapping configurations for each of the additional domains.
  • Only for specific domains.

For alternatives, see Identity Mapping Back Ends.

Benefits and Drawbacks


  • All domain users and groups whose calculated UID and GID is within the configured range are automatically available on the domain member.
  • You do not need to manually assign IDs, home directories, and login shells.
  • No duplicate IDs, even if multiple objects in a multi-domain environment have the same RID.


  • User and group IDs are not equal across Samba domain members.
  • All domain users get the same login shell and home directory assigned. However, you can use variables.
  • You can not exclude individual users or groups from being available on the domain member, except the calculated UID or GID is outside of the configured range.

Configuring the autorid Back End

To configure a Samba domain member to use the autorid ID mapping back end for the SAMDOM domain:

  • Edit the [global] section in your smb.conf file
  • Enable the autorid ID mapping back end for the SAMDOM domain:
idmap config SAMDOM : backend = autorid
  • Set a range that is big enough to assign IDs for all existing and future objects. For example:
idmap config SAMDOM : range = 10000-24999999
Samba ignores users and groups whose calculated IDs in this domain are not within the range. For details about how the back end calculated IDs, see the THE MAPPING FORMULAS in the idmap_autorid(8) man page.
  • Optionally, set a range size. For example:
idmap config SAMDOM : rangesize = 200000
Samba assigns this number of continuous IDs for each domain's object until all IDs from the range set in the idmap config SAMDOM : range parameter are taken. For further details, see the rangesizeparameter description in the idmap_autorid(8) man page.
  • Set a shell and home directory path that will be assigned to all mapped users. For example:
template shell = /bin/bash
template homedir = /home/%U
For details about variable substitution, see the VARIABLE SUBSTITUTIONS section in the smb.conf(5) man page.
  • Optionally, add additional ID mapping configurations for domains. If no configuration for an individual domain is available, Samba calculates the ID using the autorid back end settings in the previously configured * default domain.
  • Reload the Samba configuration:
# smbcontrol all reload-config

Additional Resources

  • idmap_autorid(8) man page