1IDMAP_AUTORID(8) System Administration tools IDMAP_AUTORID(8)
2
6 idmap_autorid - Samba's idmap_autorid Backend for Winbind
7
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.
12 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.
18 The mappings of which domain is mapped to which range is stored in
20 autorid.tdb, thus you should backup this database regularly.
21 Due to the algorithm being used, it is the module that is most easy to
23 use as it only requires a minimal configuration.
24
26 range = low - high
27 Defines the available matching uid and gid range for which the
28 backend is authoritative. Note that the range acts as a filter. If
29 algorithmically determined UID or GID fall outside the range, they
30 are ignored and the corresponding map is discarded. It is intended
31 as a way to avoid accidental UID/GID overlaps between local and
32 remotely defined IDs. Note that the range should be a multiple of
33 the rangesize and needs to be at least twice as large in order to
34 have sufficient id range space for the mandatory BUILTIN domain.
35 With a default rangesize of 100000 the range needs to span at least
36 200000. This would be: range = 100000 - 299999.
37 rangesize = numberofidsperdomain
39 Defines the number of uids/gids available per domain range. The
40 minimum needed value is 2000. SIDs with RIDs larger than this value
41 will be mapped into extension ranges depending upon number of
42 available ranges. If the autorid backend runs out of available
43 ranges, mapping requests for new domains (or new extension ranges
44 for domains already known) are ignored and the corresponding map is
45 discarded.
46 Example: with rangesize set to 10000, users/groups with a RID up to
48 10000 will be put into the first range for the domain. When
49 attempting to map the an object with a RID of 25000, an extension
50 range will be allocated that will then be used to map all RIDs from
51 20000-29999.
52 One range will be used for local users and groups and for
54 non-domain well-known SIDs like Everyone (S-1-1-0) or Creator Owner
55 (S-1-3-0). A chosen list of well-known SIDs will be preallocated on
56 first start to create deterministic mappings for those.
57 Thus the number of local users and groups that can be created is
59 limited by this option as well. If you plan to create a large
60 amount of local users or groups, you will need set this parameter
61 accordingly.
62 The default value is 100000.
64 read only = [ yes | no ]
66 Turn the module into read-only mode. No new ranges will be
67 allocated nor will new mappings be created in the idmap pool.
68 Defaults to no.
69 ignore builtin = [ yes | no ]
71 Ignore any mapping requests for the BUILTIN domain. Defaults to no.
72
74 The Unix ID for a RID is calculated this way:
75 ID = REDUCED RID + IDMAP RANGE LOW VALUE + RANGE NUMBER * RANGE SIZE
77 where REDUCED RID = RID % RANGE_SIZE and a DOMAIN RANGE INDEX = RID /
80 RANGE_SIZE is used together with the domain sid to determine the RANGE
81 NUMBER (stored in the database).
82 Correspondingly, the formula for calculating the RID for a given Unix
84 ID is this:
85 RID = (ID - LOW ID) % RANGE SIZE + DOMAIN RANGE INDEX * RANGE SIZE
87 Where the DOMAIN RANGE INDEX is retrieved from the database along with
90 the domain sid by the RANGE NUMBER = (ID - LOW ID) / RANGE SIZE .
91
93 This example shows you the minimal configuration that will work for the
94 principal domain and 19 trusted domains / range extensions.
95 [global]
97 security = ads
98 workgroup = CUSTOMER
99 realm = CUSTOMER.COM
100 idmap config * : backend = autorid
102 idmap config * : range = 1000000-1999999
103 This example shows how to configure idmap_autorid as default for all
107 domains with a potentially large amount of users plus a specific
108 configuration for a trusted domain that uses the SFU mapping scheme.
109 Please note that idmap ranges and sfu ranges are not allowed to
110 overlap.
111 [global]
113 security = ads
114 workgroup = CUSTOMER
115 realm = CUSTOMER.COM
116 idmap config * : backend = autorid
118 idmap config * : range = 1000000-19999999
119 idmap config * : rangesize = 1000000
120 idmap config TRUSTED : backend = ad
122 idmap config TRUSTED : range = 50000 - 99999
123 idmap config TRUSTED : schema_mode = sfu
124
127 The original Samba software and related utilities were created by
128 Andrew Tridgell. Samba is now developed by the Samba Team as an Open
129 Source project similar to the way the Linux kernel is developed.
130Samba 4.16.2 06/13/2022 IDMAP_AUTORID(8)