[cifs-protocol] [REG: 116022513755175] Modifying msDS-SupportedEncryptionTypes attribute after domain join

Sreekanth Nadendla srenaden at microsoft.com
Fri Mar 11 19:33:35 UTC 2016

Hello Andreas, 
                          Your interpretation is correct as you've stated in your e-mail below. Please do not hesitate to contact me if you have any other questions. 

Sreekanth Nadendla
Microsoft Windows Open Specifications

-----Original Message-----
From: Andreas Schneider [mailto:asn at samba.org]
Sent: Thursday, February 25, 2016 5:56 AM
To: Interoperability Documentation Help <dochelp at exchange.microsoft.com>
Cc: cifs-protocol at cifs.org; pfif at tridgell.net
Subject: Modifying msDS-SupportedEncryptionTypes attribute after domain join

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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