[Samba] Shares and AD users with winbind

[Javier Martí]

Hi!

I have a problem with a Samba share, in a Windows 2003 AD Domain, I am 
setting up a machine with Ubuntu 14.04 and Samba 4.1.6 into the AD and I 
want to make a samba share but I need to use the format user at fqdn to 
mount the share in a Windows 7 but I have a no_such_user error.

¿It is possible to use this format?

If I use the format DOMAIN\user it works perfect, ¿can I change the 
behavior?

My smb.conf:

[global]
    workgroup = REALM
    security = domain
    realm = FQDN
    encrypt passwords = yes
    log level = 3
    log file = /var/log/samba/%m.log
    idmap config *:backend = rid
    idmap config *:range = 5000-100000
    winbind allow trusted domains = yes
    winbind trusted domains only = no
    winbind use default domain = no
    winbind enum users  = yes
    winbind enum groups = yes
    winbind refresh tickets = yes
    template shell = /bin/bash
    winbind nested groups = yes
[smbserver]
    comment = smbserver
    path = /opt/smbserver
    browseable = yes
    guest ok = yes
    read only = no
    valid users = @"domain users at fqdn"

And my error in /var/samba/auth/IP.log:

/[2015/06/15 18:07:25.091446,  3] 
../source3/auth/auth.c:177(auth_check_ntlm_password)/
/  check_ntlm_password:  Checking password for unmapped user 
[]\[user at fqdn]@[PCSOURCE] with the new password interface/
/[2015/06/15 18:07:25.091482,  3] 
../source3/auth/auth.c:180(auth_check_ntlm_password)/
/  check_ntlm_password:  mapped user is: [PCTARGET]\[user at fqdn]@[PCSOURCE]/
/[2015/06/15 18:07:25.091568,  3] 
../source3/auth/check_samsec.c:399(check_sam_security)/
/  check_sam_security: Couldn't find user 'user at fqdn' in passdb./
/[2015/06/15 18:07:25.091610,  3] 
../source3/auth/auth_winbind.c:60(check_winbind_security)/
/  check_winbind_security: Not using winbind, requested domain 
[PCTARGET] was for this SAM./
/[2015/06/15 18:07:25.091642,  2] 
../source3/auth/auth.c:288(auth_check_ntlm_password)/
/  check_ntlm_password:  Authentication for user [user at fqdn] -> 
[user at fqdn] FAILED with error NT_STATUS_NO_SUCH_USER/
/[2015/06/15 18:07:25.091687,  2] 
../auth/gensec/spnego.c:743(gensec_spnego_server_negTokenTarg)/
/  SPNEGO login failed: NT_STATUS_NO_SUCH_USER/
/[2015/06/15 18:07:25.092851,  3] 
../source3/smbd/server_exit.c:212(exit_server_common)/
/  Server exit (NT_STATUS_CONNECTION_RESET)/

But, if I use DOMAIN\user:

/[2015/06/15 18:12:38.262123,  3] 
../source3/auth/auth.c:177(auth_check_ntlm_password)//
//  check_ntlm_password:  Checking password for unmapped user 
[DOMAIN]\[user]@[PCSOURCE] with the new password interface//
//[2015/06/15 18:12:38.262199,  3] 
../source3/auth/auth.c:180(auth_check_ntlm_password)//
//  check_ntlm_password:  mapped user is: [DOMAIN]\[user]@[PCSOURCE]//
//[2015/06/15 18:12:38.372607,  3] 
../source3/auth/auth.c:226(auth_check_ntlm_password)//
//  check_ntlm_password: winbind authentication for user [user] succeeded//
//[2015/06/15 18:12:38.372708,  2] 
../source3/auth/auth.c:278(auth_check_ntlm_password)//
//  check_ntlm_password:  authentication for user [user] -> [user] -> 
[DOMAIN\user] succeeded//
//[2015/06/15 18:12:38.372774,  3] 
../auth/ntlmssp/ntlmssp_sign.c:547(ntlmssp_sign_init)//
//  NTLMSSP Sign/Seal - Initialising with flags://
//[2015/06/15 18:12:38.372811,  3] 
../auth/ntlmssp/ntlmssp_util.c:34(debug_ntlmssp_flags)//
//  Got NTLMSSP neg_flags=0xe2088215//
//[2015/06/15 18:12:38.375181,  3] 
../source3/groupdb/mapping.c:830(pdb_create_builtin_alias)//
//  pdb_create_builtin_alias: Could not get a gid out of winbind//
//[2015/06/15 18:12:38.375250,  2] 
../source3/auth/token_util.c:456(finalize_local_nt_token)//
//  WARNING: Failed to create BUILTIN\Administrators group! Can Winbind 
allocate gids?//
//[2015/06/15 18:12:38.376633,  3] 
../source3/groupdb/mapping.c:830(pdb_create_builtin_alias)//
//  pdb_create_builtin_alias: Could not get a gid out of winbind//
//[2015/06/15 18:12:38.376700,  2] 
../source3/auth/token_util.c:480(finalize_local_nt_token)//
//  WARNING: Failed to create BUILTIN\Users group! Can Winbind allocate 
gids?//
//[2015/06/15 18:12:38.377999,  3] 
../source3/smbd/password.c:144(register_homes_share)//
//  Adding homes service for user 'DOMAIN\user' using home directory: 
'/home/DOMAIN/user'/

¿Something for investigate?

Thank you all in advance