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Re: [Samba] samba 4 ad member - idmap = ad for machine accounts

Thanks for quick reply.

File server config looks exactly like this, except more shares, all with same simple config. I know that "use defualt domain" isn't necessery, but it's not the issue for me right now.

       netbios name = VS-FILES
       security = ADS
       workgroup = MYDOMAIN
       realm = MYDOMAIN.COM

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

       idmap config *:backend = tdb
       idmap config *:range = 100-2000

       idmap config MYDOMAIN:backend = ad
       idmap config MYDOMAIN:schema_mode = rfc2307
       idmap config MYDOMAIN:range = 4000-99999

        winbind enum users = yes
        winbind enum groups = yes
        winbind nested groups = yes
        winbind expand groups = 5
        winbind use default domain = yes
        winbind nss info = rfc2307
        vfs objects = acl_xattr
        map acl inherit = yes
        store dos attributes = yes

        path = /home/shares/SOME_SHARE/
        read only = no

Some uses I have for machine accounts:
1) I have v. important windows application that is running as windows service as "SYSTEM" account. It writes a lot of image-type files. Because it's running as SYSTEM, machine account has to have "read/write" to the share. 2)'m using some machine autostart scripts, for various tasks, which work again as SYSTEM, so if they have to get anything from network share, they need to have read/write permission. What I'm doing is, for example, as autostart run a batch script, that would check \\fileserver\public\test-file.txt if %COMPTURNAME% exists in this file. if not - run some robocopy script, then >> %COMPUTERNAME% to the end of the file.
or even something simple like this:
"if exist \\server\share\%computername%.txt (exit)
else robocopy some-files
echo . > \\server\share\%computername%.txt
3) Some windows applications that I use also run as SYSTEM account and they have built-in backup utilities, and if I want to backup straight to network share - again - machine account needs direct write access to share.

I do know that machine accounts are "normal" accounts, and I tried simply adding them to windows ACL, but it just tidn't work. I had to go with "idmap = rid", and it did just fine, so the issue must be iwth idmap backend - ad not supplying valid uid for winbind, right?

W dniu 2017-09-17 o 19:50, Rowland Penny via samba pisze:
On Sun, 17 Sep 2017 18:14:45 +0200
Kacper Wirski via samba <samba@xxxxxxxxxxxxxxx> wrote:


I have samba 4.5.10 file server as AD member (AD is also samba

I'm using unix extension for windows rsat to set UIDs for all users
and on samba AD member i'd prefer to use idmap = ad to have
consistent file permissions across multiple file servers.

My issue is with machine accounts. RSAT extension doesn't allow for
easy "uid" setting for machine accounts. I've been trying with ldap
editor to set  UID, primary group ID etc. ,but without success.

Why do I need this?
Short answer, you don't for machine accounts

When task on a PC is run as SYSTEM and should access network share,
windows will try to use it's machine account instead. I'm using some
backup tasks and other scripts that are supposed to store output in
network shares, for this to work I simply want to give read-write
permissions to machine accounts, and wit idmap = AD those accounts
have no UID.
Ah, I think you may be mistaking Kerberos machine accounts for machine
accounts. Let me guess, you come from a Samba 3 way of doing things ;-)

   With idmap = rid everything works obviously fine, but I'm not sure
how consistent permissions will be across servers.
You can get consistent IDs on Unix domain members with the 'rid'
backend, but you will have different IDs on a Samba DC

What I'm planning to do is setting idmap uid range something like
5000 - 99999, with 10,000 + for users (default setting), and use
5000+ for machines. This way I have large enough margin, so it won't
overlap with users, and it will not interfere with rsat
auto-increnemt by one.
You do not need uidNumbers for machines and I cannot recommend your
suggested ranges. You should be aware, as far as AD is concerned, a
computer is also a user.

Samba unix settings are minimal, all permissions are set using
windows GUI.
Or to put it another way, you are using Windows ACLs

My question comes down to this:

- which LDAP attributes of an AD joined windows PC should be edited,
so it will have access to samba 4 share with it's machine account,
when using idmap = AD in the same way, that domain users do, when
using NIS extension for RSAT?
I think this may be the wrong question, I think you may be better
asking how do I make my scripts work with Samba AD

Can I suggest you read this wikipage:


I have updated it today, to try and make the range setting etc a bit
more understandable.

It will definitely help if you post the smb.conf you are using on your
Unix domain member (what you call a fileserver)

As you cannot attach files to posts to this list, can I suggest you
send me (offlist) one of the scripts you are having problems with and I
will try to advise just were you may be going wrong.


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