[cifs-protocol] [REG:110122106325012] [MS-DNSP] Documentation for DNS_TYPE_ZERO (was "strange records in DNS LDAP NCs")

[Andrew Bartlett]

On Tue, 2011-01-04 at 17:36 +0000, Bryan Burgin wrote:
> Hi Tridge,
> 
> Happy new year.  I'm checking to see if you had any additional feedback on this or if you received the information you needed.

Bryan,

I think you are misunderstanding the context here.  We have found these
records in Active Directory, in the DNS application naming contexts: 

Andrew Tridgell wrote:
> There are a few aspects of the Windows DNS NCs that are puzzling us:
> 
> 1) we see records like this:
> 
> dn: DC=..SerialNo-W2K8R2B.v2.tridgell.net,DC=v2.tridgell.net,CN=MicrosoftDNS,DC=DomainDnsZones,DC=v2,DC=tridgell,DC=net
> dnsRecord:     NDR: struct dnsp_DnssrvRpcRecord
>         wDataLength              : 0x0008 (8)
>         wType                    : DNS_TYPE_ZERO (0)
>         dwFlags                  : 0x00000005 (5)
>         dwSerial                 : 0x000002b1 (689)
>         dwTtlSeconds             : 0x00000000 (0)
>         dwTimeStamp              : 0x00000000 (0)
>         dwReserved               : 0x00000000 (0)
>         data                     : union dnsRecordData(case 0)
>         data                     : DATA_BLOB length=8
> [0000] 40 47 30 F4 9F A0 CB 01                            @G0..... 
> 
> what are they for? What is in that 8 bytes of data? What is the significance of the "..SerialNo-HOSTNAME" records?
> 
> The MS-DNSP doc says:
> 
>    DNS_TYPE_ZERO         An empty record type (section 3.6 in [RFC1034] and section 3.2.2 in [RFC1035]).
>    0x0000
> 
> which isn't very useful!
> 
> 2) what is the dwReserved field in all the dnsNode records? The MS-DNSP doc says:
> 
>    dwReserved: This value MUST be set to 0x00000000 when sent by the client and ignored on
>      receipt by the server.
> 
> but that makes no sense. These are fields that are sent by the LDAP or
> DRS server in response to queries. The values are far too consistent
> to be random. 
> 
> Note that we are not asking about the DNS RPC protocol that MS-DNSP
> concentrates on. In our case Samba is a DC that is replicating the DNS
> NCs with Microsoft DCs. We need to know how to fill in these fields
> when we create records that will be replicated to MS DNS servers via
> DRS.
> 
> Cheers, Tridge


-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Cisco Inc.