[Samba] Re: Trusting and trusted domain (home mapping) problem

Igor Belyi sambauser at katehok.ac93.org
Mon Nov 1 18:51:35 GMT 2004

I would guess that it means that DomainA trust DomainB but DomainB does 
not trust DomainA. Can you verify that trust is mutual between them? 
Check 'net rpc trustom list' on both machines.

No, I do not use winbind for NSS (no winbind in /etc/nsswitch.conf). 
Winbind is used only by Samba when it maps users from trust domain into 
local space.

Adrian Chow wrote:

>Hi Igor,
>I got stuck now.  I did my best.  I got stuck at the winbind which I suspected is the reason why the domainA_computer cannot map the domain_B user's home directory.
>1.  What are the settings of your winbind?
I have the following winbind related entries in smb.conf:
  ldap idmap suffix = ou=Idmap
  idmap backend = ldap:ldap://localhost
  idmap uid = 10000-20000
  idmap gid = 10000-20000

To see if winbind works you can also try to resolve a name into SID and 
SID into gid. For examle, if wbinfo -g returns you 'STAFF\wheel'. Try to 
do the following:
wbinfo -n 'STAFF\wheel'
wbinfo -Y <SID return in a previous command>

>2.  Do you use only "winbind" in your libnss_ldap or use "ldap" as well?
In my /etc/nsswitch.conf I have only "ldap" without winbind. As far as I 
understand this, winbind usage via NSS can confuse Samba into thinking 
that those users and groups are defined locally and maybe allowing Samba 
to use winbind directly is a better approach for trust between domains.

I don't know why would you want to put winbind into libnss_ldap which is 
configuration for LDAP interface for NSS (when you use 'ldap' in 
/etc/nssswitch.conf file)

>3.  My winbind works with :-
>(For both sides)
>wbinfo -t
>wbinfo -p
>wbinfo -u
>wbinfo -g
>getent passwd
>(For DomainA)
>"getent group" shows all the local groups and also the groups shown in "wbinfo -g"
>(For DomainB)
>"getent group" shows all the local groups and only the GUESTs group.  Very weird.  The rest of the groups in "wbinfo -g" does not come up. 
>The logs is something like this:-
>  could not lookup membership for group rid S-1-5-21-1803233979-822103454-943392455-3005 in domain STAFF (error: NT_STATUS_NO_SUCH_GROUP)
>[2004/11/01 00:13:10, 0] nsswitch/winbindd_group.c:winbindd_getgrent(795)
>  could not lookup domain group STAFF\wheel
Do you mean that this error message was reported during "getent group" 
in DomainB? Because, without this error message I would assume that you 
have winbind written in /etc/nsswithc.conf on your DomainA server but 
not on your DomainB server.

The error message means that Samba thinks that 'wheel' is a Domain group 
of the 'STAFF' domain and fails to find its mapping. I would expect this 
error to come up during login of a Domain user whose primary group is a 
local 'wheel' group instead of a Domain group. If this user is supposed 
to have 'wheel' as a primary group you probably forgot to create a 
groupmap from a Domain group for it.


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