1IDMAP_AUTORID(8)          System Administration tools         IDMAP_AUTORID(8)
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NAME

6       idmap_autorid - Samba´s idmap_autorid Backend for Winbind
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DESCRIPTION

9       The idmap_autorid backend provides a way to use an algorithmic mapping
10       scheme to map UIDs/GIDs and SIDs that is more deterministic than
11       idmap_tdb and easier to configure than idmap_rid.
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13       The module works similar to idmap_rid, but it automatically configures
14       the range to be used for each domain, so there is no need to specify a
15       specific range for each domain in the forest, the only configuration
16       that is needed is the range of uid/gids that shall be used for
17       user/group mappings and an optional size of the ranges to be used.
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19       The mappings of which domain is mapped to which range is stored in
20       autorid.tdb, thus you should backup this database regularly.
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22       Due to the algorithm being used, it is the module that is most easy to
23       use as it only requires a minimal configuration.
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IDMAP OPTIONS

26       rangesize = numberofidsperdomain
27           Defines the number of uids/gids available per domain range. The
28           minimum needed value is 2000. SIDs with RIDs larger than this value
29           will be mapped into extension ranges depending upon number of
30           available ranges. If the autorid backend runs out of available
31           ranges, mapping requests for new domains (or new extension ranges
32           for domains already known) are ignored and the corresponding map is
33           discarded.
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35           Example: with rangesize set to 10000, users/groups with a RID up to
36           10000 will be put into the first range for the domain. When
37           attempting to map the an object with a RID of 25000, an extension
38           range will be allocated that will then be used to map all RIDs from
39           20000-29999.
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41           One range will be used for local users and groups and for
42           non-domain well-known SIDs like Everyone (S-1-1-0) or Creator Owner
43           (S-1-3-0). A chosen list of well-known SIDs will be preallocated on
44           first start to create deterministic mappings for those.
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46           Thus the number of local users and groups that can be created is
47           limited by this option as well. If you plan to create a large
48           amount of local users or groups, you will need set this parameter
49           accordingly.
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51           The default value is 100000.
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53       read only = [ yes | no ]
54           Turn the module into read-only mode. No new ranges will be
55           allocated nor will new mappings be created in the idmap pool.
56           Defaults to no.
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58       ignore builtin = [ yes | no ]
59           Ignore any mapping requests for the BUILTIN domain. Defaults to no.
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THE MAPPING FORMULAS

62       The Unix ID for a RID is calculated this way:
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64                          ID =  REDUCED RID + IDMAP RANGE LOW VALUE + RANGE NUMBER * RANGE SIZE
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67       where REDUCED RID = RID % RANGE_SIZE and a DOMAIN RANGE INDEX = RID /
68       RANGE_SIZE is used together with the domain sid to determine the RANGE
69       NUMBER (stored in the database).
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71       Correspondingly, the formula for calculating the RID for a given Unix
72       ID is this:
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74                          RID = (ID - LOW ID) % RANGE SIZE + DOMAIN RANGE INDEX * RANGE SIZE
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77       Where the DOMAIN RANGE INDEX is retrieved from the database along with
78       the domain sid by the RANGE NUMBER = (ID - LOW ID) / RANGE SIZE .
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EXAMPLES

81       This example shows you the minimal configuration that will work for the
82       principal domain and 19 trusted domains / range extensions.
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84                [global]
85                security = ads
86                workgroup = CUSTOMER
87                realm = CUSTOMER.COM
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89                idmap config * : backend = autorid
90                idmap config * : range = 1000000-1999999
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94       This example shows how to configure idmap_autorid as default for all
95       domains with a potentially large amount of users plus a specific
96       configuration for a trusted domain that uses the SFU mapping scheme.
97       Please note that idmap ranges and sfu ranges are not allowed to
98       overlap.
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100                [global]
101                security = ads
102                workgroup = CUSTOMER
103                realm = CUSTOMER.COM
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105                idmap config * : backend = autorid
106                idmap config * : range = 1000000-19999999
107                idmap config * : rangesize = 1000000
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109                idmap config TRUSTED : backend  = ad
110                idmap config TRUSTED : range    = 50000 - 99999
111                idmap config TRUSTED : schema_mode = sfu
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AUTHOR

115       The original Samba software and related utilities were created by
116       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
117       Source project similar to the way the Linux kernel is developed.
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121Samba 4.2                         06/19/2018                  IDMAP_AUTORID(8)
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