[Samba] inconsistent DNS information, windows domain member issues..

Wed Jun 8 19:47:55 UTC 2016

I am omitting a lot of old stuff..

>    -----Ursprüngliche Nachricht-----
>    Von: samba [mailto:samba-bounces at lists.samba.org] Im Auftrag von
>    mathias dufresne
>    Gesendet: Montag, 6. Juni 2016 12:01
>    An: Rowland penny <rpenny at samba.org>
>    Cc: samba <samba at lists.samba.org>; Jo <j.o.l at live.com>
>    Betreff: Re: [Samba] inconsistent DNS information, windows domain
>    member issues..
>    
>    To regenerate dns.keytab I expect you only need to relaunch
>    samba_upgradedns --dns-backend=BIND9_DLZ.
>    If I'm wrong (it happens quiet often) you would have to first launch:
>    samba_upgradedns --dns-backend=SAMBA_INTERNAL and then
>    samba_upgradedns --dns-backend=BIND9_DLZ
>    
>    Here you should have a dns.keytab.
>    
Worked, thanks a lot.

>    Now, right issues: dns related files in samba/private must be accessible to
>    the UNIX user running Bind process. That means changing rights on files
>    and on private (at least "x" permission to go through it).
>    
My bind is running as root right now, and the authorizations look ok to me. Also don´t see log entries that contradict that.

>    And another note about 'islanding': this issue does not exist on recent
>    Samba. In fact I never had this issue with any of Samba version we tried,
>    and we tried almost all since 4.1.x (a big year). The issue wasn't there
>    when we tried to make Samba's internal DNS working (what we stopped)
>    and is not there also using Bind9+DLZ DNS backend.
>    Islanding (https://support.microsoft.com/en-us/kb/275278) is solved in
>    MS Windows Server 2012. It's a stupid bug from MS, they - as everyone -
>    do mistakes sometimes. Samba team also do mistakes sometimes, but
>    that one wasn't reproduced. Islanding does not exist with Samba AD DC.
>    
>    Obviously you can use localhost as DNS resolver only once you have
>    joined the DC to the domain and after replication happened. Otherwise
>    your new DC will have empty DNS zones and so no reply.
>    
>    If my English understanding is correct enough this was even told by
>    Andrew Bartlett in a mail from May the 26th around 20h20 UTC, the title
>    was "[Samba] DC2: TKEY is unacceptable, Failed DNS update?":
>    "Yes, it should use itself as the DNS server, once the initial registration
>    work is done."
>    
I am also not a native speaker in English but my take is the same.

>    2016-06-05 20:46 GMT+02:00 Rowland penny <rpenny at samba.org>:
[dropped lots]

Now with the changes I still get the following in the log of dc2, at least occasionally.

[2016/06/08 20:10:13.832105,  0] ../source4/librpc/rpc/dcerpc_sock.c:240(continue_ip_open_socket)
  Failed to connect host 192.168.177.21 (7fb38333-aced-4ce8-9a15-a3f6459ecc2a._msdcs.samba.lindenberg.one) on port 135 - NT_STATUS_CONNECTION_REFUSED.

I write occasionally because  I tried restarting samba on dc2 and then the message did not appear.

Nothing suspicious in log of dc1.

Getting back to my initial issue list:

>    -----Ursprüngliche Nachricht-----
>    Von: samba [mailto:samba-bounces at lists.samba.org] Im Auftrag von Jo
>    Gesendet: Sonntag, 5. Juni 2016 11:06
>    An: 'samba' <samba at lists.samba.org>
>    Betreff: [Samba] inconsistent DNS information, windows domain member
>    issues..
>    
>    I joined a Windows 10 Pro system to my (still experimental) domain. The
>    windows system actually hosts DC2 as a VM, and another Windows
>    (Server 2008
>    R2) at another location hosts DC1 also as a VM. The two locations are
>    connected via a VPN, both systems run only when needed. The windows
>    system does not directly use DC2 for DNS but instead talks to a DNS
>    resolver that delegates the samba Domain to DC2. DC2 uses itself as
>    nameserver.
>    
>    
>    
>    I am observing the following issues that may be related or not:
>    
>    *       When I do a nslookup samba.domain DC2 I get the address of DC1,
>    nslookup DC2.sambadomain DC2 fails. Nslookup DC1.samba.domain DC2
>    works.
>    When I use dig @DC2 samba.domain it returns DC1 only. Dig
>    samba.domain ANY returns
>    

Dig reports now the same information on dc1 and dc2. However it reports the old and the new IP address of DC2. I was able to clean this up by deleting the extra A record. Afterwards the extra A record was gone. Same for nslookup on Ubuntu.

>    *       windows nslookup -type=ANY samba.domain (without .) looks for
>    samba.domain.domain. Is this OK or does it point to a problematic search
>    configuration?
>    
Works properly now. DNS mmc snap-in shows consistent information.

>    
>    *       In windows management console, only some of the domain
>    users&principals are shown with the name domain\identity, most of them
>    are shown S-xxx. With the one use shown domain\user I can logon to the
>    windows system however (likely with cached credentials, but don´t dare
>    to change them to confirm)
>    
>    *       When I try to modify folder permissions on the windows system, I
>    get
>    a message “Unable to contact Active Directory to access or verify claim
>    types”
>    
These two issues still exist.

>    *       On DC2: kinit Administrator returns “kinit: Cannot contact any KDC
>    for realm ‘samba.domain’ while getting initial credentials. This one was
>    easy to fix by adding the domain to /etc/krb5.conf. I am putting this in as I
>    changed configuration at this point..
>    
Working.

In essence, the windows member is unable to use any information from Samba. The lookup described in https://wiki.samba.org/index.php/Testing_DNS_Name_Resolution does work and reports both dcs as expected.
I checked the Windows system log. There is some noise about group policies and missing updates of the host address. The most relevant record shows:
"This computer was not able to set up a secure session with a domain controller in domain SAMBA due to the following: 
There are currently no logon servers available to service the logon request. 
This may lead to authentication problems. Make sure that this computer is connected to the network. If the problem persists, please contact your domain administrator.  

ADDITIONAL INFO 
If this computer is a domain controller for the specified domain, it sets up the secure session to the primary domain controller emulator in the specified domain. Otherwise, this computer sets up the secure session to any domain controller in the specified domain."

Looks like Windows 10 Pro expects encrypted configuration by default - which is totally OK to me. But which connection(s)? LDAP as in https://wiki.samba.org/index.php/Configuring_LDAP_over_SSL_(LDAPS)_on_a_Samba_AD_DC? And what certificates does a Windows host trust by default. I can easily use a Letsencrypt certificate if that is OK to windows..

Thanks once more for your support.
Joachim