[Samba] Samba 4 two DCs no matching UID/GID

Rowland Penny rowlandpenny at googlemail.com
Wed Dec 10 03:01:29 MST 2014

On 09/12/14 22:49, Tim wrote:
> But will this idmap.ldb change work for upcoming new users or groups 
> so that uid/gid will not be different?
> The wiki tells us about built-in groups. Those have the right ids.
> Am 9. Dezember 2014 23:03:44 MEZ, schrieb Rowland Penny 
> <rowlandpenny at googlemail.com>:
>     On 09/12/14 21:07, Tim wrote:
>         Hello all, I have a fresh install of two CentOS 7 machines. On
>         DC1 I made a domain provision with --use-rfc2307. In DC2 I
>         made a join as DC - both exactly as the wiki advised. In fact
>         of its missing I added the idmap use rfc2307 yes parameter to
>         smb.conf. I will have an extra share on both DCs. Today I
>         realized, that wbinfo shows different UID/GID for the same
>         users or groups on the DC's. I created the users/groups via
>         RSAT. I don't have a Unix attributes tab in RSAT. Is that my
>         problem for different uid/gid? Thanks in advance Tim 
>     Hi, I think your problem is that idmap.ldb does not replicate to the new
>     DC, this means that users get different UID's on the two DC's.
>     If you run:
>     ldbedit -e nano -H /var/lib/samba/private/idmap.ldb
>     on each DC, you will be able to see the differences.
>     The cure ? copy idmap.ldb from the first DC to any secondary DC's after
>     the join.
>     It is documented here:
>     https://wiki.samba.org/index.php/Join_a_domain_as_a_DC  , near the bottom
>     of the page.
>     Rowland

I take it that you didn't read this page on the wiki: 

You are running into one of the problems why it is not recommended to 
use the DC as a fileserver, you have two choices here, either set up a 
separate member server to use as a fileserver, or use sssd or nlscd to 
pull the RFC2307 attributes that you will need to add to the users/groups.

Whatever you do, you will need to copy idmap.ldb to any secondary DC's.


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