Jean FrançoisMicouleau
&author.jerry;
&author.jht;
Configuring Group Mapping
Starting with Samba-3, new group mapping functionality is available to create associations
between Windows group SIDs and UNIX groups. The groupmap subcommand
included with the &net; tool can be used to manage these associations.
The first immediate reason to use the group mapping on a Samba PDC, is that
the domain admin group has been removed and should no longer
be specified in &smb.conf;. This parameter was used to give the listed users membership
in the "Domain Admins" Windows group which gave local admin rights on their workstations
(in default configurations).
Features and Benefits
Stuff goes here.
Discussion
When installing MS Windows NT4 / 200x on a computer, the installation program creates default
users and groups. Notably the 'Administrators' group, and gives to that group privileges necessary
privilidges to perform essential system tasks. eg: Ability to change the date and time or to
kill any process (or close too) running on the local machine.
The 'Administrator' user is a member of the 'Administrators' group, and thus inherits
'Administrators' group privileges. If a 'joe' user is created to be a member of the
'Administrator' group, 'joe' has exactly the same rights as 'Administrator'.
When an MS Windows NT4 / W200x is made a domain member, the "Domain Adminis" group of the
PDC is added to the local 'Administrators' group of the workstation. Every member of the
'Domain Administrators' group inherits the rights of the local 'Administrators' group when
logging on the workstation.
The following steps describe how to make samba PDC users members of the 'Domain Admins' group?
create a unix group (usually in /etc/group), let's call it domadm
add to this group the users that must be Administrators. For example
if you want joe,john and mary, your entry in /etc/group will
look like:
domadm:x:502:joe,john,mary
Map this domadm group to the "Domain Admins" group by running the command:
&rootprompt;net groupmap add ntgroup="Domain Admins" unixgroup=domadm
The quotes around "Domain Admins" are necessary due to the space in the group name.
Also make sure to leave no whitespace surrounding the equal character (=).
Now joe, john and mary are domain administrators!
It is possible to map any arbitrary UNIX group to any Windows NT4 / 200x group as well as
making any UNIX group a Windows domain group. For example, if you wanted to include a
UNIX group (e.g. acct) in a ACL on a local file or printer on a domain member machine,
you would flag that group as a domain group by running the following on the Samba PDC:
&rootprompt;net groupmap add rid=1000 ntgroup="Accounting" unixgroup=acct
Be aware that the RID parmeter is a unsigned 32 bit integer that should
normally start at 1000. However, this rid must not overlap with any RID assigned
to a user. Verifying this is done differently depending on on the passdb backend
you are using. Future versions of the tools may perform the verification automatically,
but for now the burden is on you.
Example Configuration
You can list the various groups in the mapping database by executing
net groupmap list. Here is an example:
&rootprompt; net groupmap list
System Administrators (S-1-5-21-2547222302-1596225915-2414751004-1002) -> sysadmin
Domain Admins (S-1-5-21-2547222302-1596225915-2414751004-512) -> domadmin
Domain Users (S-1-5-21-2547222302-1596225915-2414751004-513) -> domuser
Domain Guests (S-1-5-21-2547222302-1596225915-2414751004-514) -> domguest
For complete details on net groupmap, refer to the net(8) man page.
Configuration Scripts
Everyone needs tools. Some of us like to create our own, others prefer to use canned tools
(ie: prepared by someone else for general use).
Common Errors
There must be some stuff that can go here!