[Samba] Domain member server: user access

Rowland Penny rpenny at samba.org
Tue Oct 10 07:57:56 UTC 2017

On Tue, 10 Oct 2017 09:19:11 +0200
"Stefan G. Weichinger via samba" <samba at lists.samba.org> wrote:

> Am 2017-10-09 um 21:57 schrieb Rowland Penny via samba:
> > On Mon, 9 Oct 2017 21:35:39 +0200
> > "Stefan G. Weichinger via samba" <samba at lists.samba.org> wrote:
> > 
> >> Am 2017-10-09 um 21:04 schrieb Rowland Penny via samba:
> >>
> >>> It isn't supposed to work like this and it didn't used to work
> >>> like this.
> >>
> >> Then the software shouldn't allow me to do so and/or give useful 
> >> feedback, don't you agree?
> > 
> > I don't see how you could be stopped from doing this, when a user or
> > group first contacts a DC, it is given an 'xidNumber' attribute in
> > idmap.ldb, containing the next available number in the 3000000'
> > range. If you decide to give this user or group a uidNumber or
> > gidNumber attribute, this should be used instead, which is what
> > happens when you run 'net cache flush'. The problem is, you
> > shouldn't have to run the 'net' command at all and you didn't used
> > to have to. If we could narrow it down to when it started not
> > working correctly, it might help.
> The admin there created a group via RSAT.
> And that group was not visible/usable on the DM server.

It wouldn't be if the group was created as just a windows group.

> Only after that I tried to figure out things on the shell, digging for
> the group on both servers via getent and wbinfo.

This would have been futile if the group was just a windows group.

> Until here there was no decision for a uidNumber or gidNumber.
> He did not set one via RSAT. Does he have to do that?

On a DC, group will be given an xidNumber and if the libnss_winbind
links are set up, this will be used, but only on that DC

On a Unix domain member, it is different, the xidNumber will not be
used, because it isn't available.
You have two main options, use the winbind 'rid' backend, with this,
provided you use the same smb.conf on all Unix domain members, you will
get the required UIDs & GIDs without adding anything to AD.
There is a 'gotcha' though, you will have to use the template lines in
smb.conf for user shell & home dirs. Your users and groups would also
have different IDs on the DC.
If you want to have the same IDs everywhere, you will have to use the
winbind 'ad' backend and give your users & groups uidNumber and
gidNumber attributes, you will also be able to use the other RFC2307

Whichever winbind backend you use on the Unix domain members, you will
also have to set up the libnss_winbind links. 

> I then deleted the group via samba-tool and created it again:
> samba-tool group create gfass --nis-domain=arbeitsgruppe
> --gid-number=10580
> If this is wrong, I am happy to learn how to do that correctly.
> I understand that running
> wbinfo --group-info="gfass"
> is problematic as long as the reported bug isn't fixed, correct?

It seems to be, but only on a DC, unless you can prove otherwise ;-)


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