Difference between revisions of "Idmap config rid"

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= Introduction =
 
= Introduction =
  
This documentation provides the basic setup for a Samba Member Server that is part of an Active Directory, using the RID backend.
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The <code>rid</code> ID mapping back end implements a read-only API to retrieve account and group information from an Active Directory (AD) Domain Controller (DC) or NT4 primary domain controller (PDC). The back end assigns IDs from an individual per-domain range set in the <code>smb.conf</code> file and stores them in them in a local database. For details, how the local ID and the relative identifier (RID) are calculated, see the <code>idmap_rid(8)</code> man page. Because the <code>rid</code> back end is read-only, it is unable to assign new ID, such as for <code>BUILTIN</code> groups. Thus this back end cannot be set as <code>idmap config *</code> default ID mapping back end.
  
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For alternatives, see [[Identity_Mapping_Back_Ends|Identity Mapping Back Ends]].
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{{Imbox
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| type = warning
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| text = ID mapping back ends are not supported in the <code>smb.conf</code> file on a Samba Active Directory (AD) domain controller (DC).<br />For details, see [[Updating_Samba#Updating_Samba#Failure_To_Access_Shares_on_Domain_Controllers_If_idmap_config_Parameters_Set_in_the_smb.conf_File|Failure to Access Shares on Domain Controllers If idmap config Parameters Set in the smb.conf File]].
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}}
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= Advantages and Disadvantages of the <code>rid</code> Back End =
 +
 +
Advantages:
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* Easy to set up.
 +
* Used IDs are tracked automatically.
 +
* Requires only read access to domain controllers.
 +
* All domain's user accounts and groups are automatically available on the domain member.
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* No attributes need to be set for domain users and groups.
 +
 +
Disadvantages:
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* All users on the domain member get the same login shell and home directory base path assigned.
 +
* User and group IDs are only the same on other domain members using the <code>rid</code> back end, if the same ID ranges are configured for the domain.
 +
* All accounts and groups are automatically available on the domain member and individual entries cannot be excluded.
  
  
== Server information ==
 
  
This documentation uses the following configuration/settings:
 
  
'''Member Server:'''
 
Installation Directory:    /usr/local/samba/
 
Member Server Hostname:    Member1
 
IP Address:                192.168.1.2
 
 
'''AD backend:
 
DNS Server:                192.168.1.1
 
DNS Domain Name:          samdom.example.com
 
Realm:                    SAMDOM.EXAMPLE.COM
 
NT4 Domain Name (NETBIOS): SAMDOM
 
  
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= Planning the ID Ranges =
  
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Before configuring the <code>rid</code> back end in the <code>smb.conf</code> file, select unique ID ranges Samba can use for each domain. The ranges must be continuous and big enough to enable Samba to assign an ID for every future user and group created in the domain.
  
== Versions ==
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{{Imbox
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| type = important
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| text = The ID ranges of the <code>*</code> default domain and all other domains configured in the <code>smb.conf</code> file must not overlap.
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}}
  
This documentation is frequently updated to reflect the latest changes. Please see the [[Samba_Release_Planning|Samba Release Planning]] for more specifics.
 
  
Please review the release notes for the version you have installed. It may contain important information, not yet reflected in this documentation.
 
  
  
  
= Set up a basic Member Server smb.conf =
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= Configuring the <code>rid</code> Back End =
  
Usually this file is located in /usr/local/samba/etc/. Depending on your 'configure' parameters, or if you are using a distro/Sernet package, it could be in a different location:
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* To configure the <code>rid</code> back end using the <code>10000-999999</code> ID range for the <code>SAMDOM</code> domain, set the following in the <code>[global]</code> section of your <code>smb.conf</code> file:
  
  [global]
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  security = ADS
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workgroup = SAMDOM
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realm = SAMDOM.EXAMPLE.COM
 
   
 
   
  netbios name = Member1
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log file = /var/log/samba/%m.log
  workgroup = SAMDOM
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log level = 1
  security = ADS
 
  realm = SAMDOM.EXAMPLE.COM
 
  dedicated keytab file = /etc/krb5.keytab
 
  kerberos method = secrets and keytab
 
 
   
 
   
  idmap config *:backend = tdb
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# Default ID mapping configuration for local BUILTIN accounts
  idmap config *:range = 2000-9999
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# and groups on a domain member. The default (*) domain:
  idmap config SAMDOM:backend = rid
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# - must not overlap with any domain ID mapping configuration!
  idmap config SAMDOM:range = 10000-99999
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# - must use a read-write-enabled back end, such as tdb.
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idmap config * : backend = tdb
  winbind trusted domains only = no
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idmap config * : range = 3000-7999
  winbind use default domain = yes
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# - You must set a DOMAIN backend configuration
  winbind enum users  = yes
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# idmap config for the SAMDOM domain
  winbind enum groups = yes
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idmap config SAMDOM : backend = rid
  winbind refresh tickets = Yes
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idmap config SAMDOM : range = 10000-999999
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[demoshare]
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{{Imbox
  path = /srv/samba/test
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| type = important
  read only = no
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| text = Setting the default back end is mandatory.
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}}
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{{Imbox
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| type = important
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| text = For every domain, set these parameters individually. The ID ranges of the <code>*</code> default domain and all other domains configured in the <code>smb.conf</code> file must not overlap.
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}}
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This very basic example will allow your Member Server to join your Active Directory, it also a known working example if your user & group IDs start at 10000.
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* Configure the template settings. For example, to set <code>/bin/bash</code> as shell and <code>/home/%U</code> as home directory path, add:
  
In the example configuration, ID mapping for domain users/groups is done via an algorithm using the objects RID retrieved from AD. This algorithm is:
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# Template settings for login shell and home directory
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template shell = /bin/bash
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template homedir = /home/%U
  
ID = RID - BASE_RID + LOW_RANGE_ID.
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The values are applied to all users in all domains. Samba resolves the <code>%U</code> variable to the session user name. For details, see the <code>VARIABLE SUBSTITUTIONS</code> section in the <code>smb.conf(5)</code> man page.
  
Which, from the numbers given above for SAMDOM, BASE_RID = 0 (the default), and a users RID of 1145, becomes:
 
  
ID = 1145 - 0 + 10000
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* Reload Samba:
  
Which means:
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# smbcontrol all reload-config
  
ID = 11145
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For further details, see the <code>smb.conf(5)</code> and <code>idmap_rid(8)</code> man page.
  
Whilst the ID numbers will now be created automatically, you should note that these numbers will be different from the ones on the DC.
 
  
If you need to use different UID/GID ranges than those shown in the example above, you will have to change them in your smb.conf.
 
  
An alternative to the RID backend is the [[Setup_a_Samba_AD_Member_Server#Set_up_a_basic_Member_Server_smb.conf|AD_backend]].
 
  
The above configuration will cause the mappings for non-domain accounts (i.e. the local Administrator, etc.) to be stored in a TDB file and the IDs are taken from the range given. The local '*' range <u>must not</u> overlap with the one specified for your domain!
 
  
'''For further explanation on the smb.conf parameters and idmap parameters, check out the manpages.'''
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----
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[[Category:Active Directory]]
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[[Category:Domain Members]]
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[[Category:NT4 Domains]]

Latest revision as of 13:53, 26 February 2019

Introduction

The rid ID mapping back end implements a read-only API to retrieve account and group information from an Active Directory (AD) Domain Controller (DC) or NT4 primary domain controller (PDC). The back end assigns IDs from an individual per-domain range set in the smb.conf file and stores them in them in a local database. For details, how the local ID and the relative identifier (RID) are calculated, see the idmap_rid(8) man page. Because the rid back end is read-only, it is unable to assign new ID, such as for BUILTIN groups. Thus this back end cannot be set as idmap config * default ID mapping back end.

For alternatives, see Identity Mapping Back Ends.



Advantages and Disadvantages of the rid Back End

Advantages:

  • Easy to set up.
  • Used IDs are tracked automatically.
  • Requires only read access to domain controllers.
  • All domain's user accounts and groups are automatically available on the domain member.
  • No attributes need to be set for domain users and groups.

Disadvantages:

  • All users on the domain member get the same login shell and home directory base path assigned.
  • User and group IDs are only the same on other domain members using the rid back end, if the same ID ranges are configured for the domain.
  • All accounts and groups are automatically available on the domain member and individual entries cannot be excluded.



Planning the ID Ranges

Before configuring the rid back end in the smb.conf file, select unique ID ranges Samba can use for each domain. The ranges must be continuous and big enough to enable Samba to assign an ID for every future user and group created in the domain.



Configuring the rid Back End

  • To configure the rid back end using the 10000-999999 ID range for the SAMDOM domain, set the following in the [global] section of your smb.conf file:
security = ADS
workgroup = SAMDOM
realm = SAMDOM.EXAMPLE.COM

log file = /var/log/samba/%m.log
log level = 1

# Default ID mapping configuration for local BUILTIN accounts
# and groups on a domain member. The default (*) domain:
# - must not overlap with any domain ID mapping configuration!
# - must use a read-write-enabled back end, such as tdb.
idmap config * : backend = tdb
idmap config * : range = 3000-7999
# - You must set a DOMAIN backend configuration
# idmap config for the SAMDOM domain
idmap config SAMDOM : backend = rid
idmap config SAMDOM : range = 10000-999999


  • Configure the template settings. For example, to set /bin/bash as shell and /home/%U as home directory path, add:
# Template settings for login shell and home directory
template shell = /bin/bash
template homedir = /home/%U

The values are applied to all users in all domains. Samba resolves the %U variable to the session user name. For details, see the VARIABLE SUBSTITUTIONS section in the smb.conf(5) man page.


  • Reload Samba:
# smbcontrol all reload-config

For further details, see the smb.conf(5) and idmap_rid(8) man page.