[Samba] unknown authentification failure - Samba 4.0.1 pdc

Rowland Penny rowlandpenny at googlemail.com
Mon Oct 28 10:08:35 MDT 2013

On 28/10/13 15:36, bugblatterbeast wrote:
> 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] 
> ../auth/ntlmssp/ntlmssp_sign.c:236(ntlmssp_check_packet)
>   NTLMSSP NTLM2 packet check failed due to invalid signature!
> [2013/10/28 14:47:38,  0] 
> ../auth/ntlmssp/ntlmssp_sign.c:236(ntlmssp_check_packet)
>   NTLMSSP NTLM2 packet check failed due to invalid signature!
> [2013/10/28 14:47:48,  0] 
> ../source4/rpc_server/drsuapi/writespn.c:237(dcesrv_drsuapi_DsWriteAccountSpn)
>   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
Hi, it might help if you opened another post rather than jumping into 
the middle of a discussion, also a lot more info is going to be needed. 
i.e. what version(s) of samba are you running, what OS's are you using, 
smb.conf etc.


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