[cifs-protocol] Modifying msDS-SupportedEncryptionTypes attribute after domain join

Andreas Schneider asn at samba.org
Thu Feb 25 10:55:37 UTC 2016

Hello, dochelp!

G√ľnther Deschner and I looked into updating the msDS-SupportedEncryptionTypes 
attribute after a domain join.

We would like to ask for some clarifications for:

--- snip ---
[MS-KILE] msDS-SupportedEncryptionTypes attribute:

"If the realm is a KILE implementation that uses an Active Directory for the 
account database, the server SHOULD ensure that the msDS-
SupportedEncryptionTypes attribute ([MS-ADA2] section 2.458) of its account 
object is set to the value of SupportedEncryptionTypes (section

When an application server is running under the machine account and NRPC is 
supported on the machine, the server SHOULD call NetrLogonGetDomainInfo ([MS-
NRPC] section with the Level parameter set to 1 and 
WkstaBuffer.WorkstationInfo.KerberosSupportedEncryptionTypes set to 
zero.<72>If the WkstaBuffer.WorkstationInfo.KerberosSupportedEncryptionTypes 
returned is not equal to SupportedEncryptionTypes (section, then LDAP 
is used to update the setting:<73>

2.    Establish an LDAP connection with server information set to NULL
      ([MS-ADTS] section 7.1).

1.    Perform an LDAP modify operation to set the
      msDS-SupportedEncryptionTypes attribute ([MS-ADA2] section 2.458) of the
      computer account object to the value of SupportedEncryptionTypes
--- snip-end ---

Do we interpret that correctly, that after the machine account has been added 
to Active directory, a netlogon connection is established using the machine 
account credentials from the machine account we just created.

NetrLogonGetDomainInfo() is called to retrieve the information if the 
supported encryption types need to be changed or not. If it needs to be 

1. An LDAP connection with the credentials of the newly created machine
   account is established
2. We perform an LDAP modify operation to set the
   msDS-SupportedEncryptionTypes attribute

Is that correct?


Best regards,

	-- andreas

Andreas Schneider                   GPG-ID: CC014E3D
Samba Team                             asn at samba.org

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