[Samba] unknown authentification failure - Samba 4.0.1 pdc

bugblatterbeast samba at bugblatterbeast.de
Mon Oct 28 09:36:32 MDT 2013

I've just found something in a logfile named "log.%m" (usually the name 
of the machine is filled in):

[2013/10/28 14:46:19,  0] 
   NTLMSSP NTLM2 packet check failed due to invalid signature!
[2013/10/28 14:47:38,  0] 
   NTLMSSP NTLM2 packet check failed due to invalid signature!
[2013/10/28 14:47:48,  0] 
   Failed to modify SPNs on 
CN=COMPUTERNAME,CN=Computers,DC=DOMAINNAME,DC=local: error in module 
acl: Constraint violation (19)

This seems to be important... but I still don't understand what it means 
and how I can fix it.

Am 28.10.2013 15:26, schrieb bugblatterbeast:
> Hi,
>     one of our clients can't connect to the pdc anymore. All attempts 
> lead to an error-message about the wrong username or password. We've 
> tried several user-accounts and it's always the same...
> any username like "domainname\domainuser" with password always fails 
> without delay. Either when trying to log on to the workstation, or 
> when connecting to a samba share on the domain-controller (like 
> "\\domaincontroller\share").
> Now, when we log in as a local user and try to connect to a samba 
> share on the domain-controller using the WRONG username 
> "computername\domainuser" with the NOT MATCHING password of the 
> domainuser it works!!!!! We can not only connect to a samba share but 
> also join or leave the domain. However it's still impossible to logon 
> to the workstation that way...
> We've also changed the ip-address and the netbios-name of the computer 
> and deleted the computer's domain-account... several times without any 
> success.
> The most disappointing thing is, that I can't find any log-entries on 
> the domain controller. I've already activated machine-logs, but 
> there's nothing helpful to be found in /var/log/samba.
> Thanks in advance, bbb

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