R: Heuristics for finding a Win2K domain controller ...

[Richard Sharpe]

On Fri, 3 May 2002, PINTO ELIA wrote:

Hi Pinto,

This was the most detailed and useful answer I got.

Since I have to be able to find both NT4 and Win2K DCs, my approach will 
be to try WINS first, and if that fails, try DNS as you outline below.

Of couse, I have to do all this in TCL, but that's life :-)

> Try standard DNS query as follow.
> 
> A windows 2000 domain is represented by a DNS domain name. Each domain
> controller
> register its address with DNS using the standard DNS dynamic update (RFC
> 2136 ). In
> addition to register its host name (A record ), the domain controller
> registers pseudonym(s)
> (SRV or CNAME records ) that will help finding the DC based on predictable
> criteria (e.g. the DC in a particular site ). If multiple DC have the same
> criteria, then there would be
> multiple records with the same pseudonym. A client locking for a DC with
> that criteria would
> receive all the applicable records from the DNS server. 
> 
> For example, a DC named spiros in the domain nt.egge.com with an IP address
> of 192.68.1.1 
> would register the following records with DNS:
> 
> spiros.nt.egge.com.			A 		192.68.1.1
> _ldap._tcp.nt.egge.com.  		SRV 		0 0 389
> spiros.nt.egge.com.
> _kerberos._tcp.nt.egge.com. 	SRV 		0 0 99 spiros.nt.egge.com.
> _ldap._tcp.dc._msdcs.nt.egge.com.	SRV	0 0 389 spiros.nt.egge.com.
> _kerberos._tcp.dc._msdcs.nt.egge.com. SRV 0 0 99 spiros.nt.egge.com.
> 
> with these record in place ( and similar record by all the other DCs in the
> same domain)
> a simple lookup of "_ldap._tcp.dc._msdcs.nt.egge.com" will return the names
> and address of all
> the DCs in the domain. 
> 
> In short the query for finding all the DCs is:
> _ldap._tcp.dc._msdcs.<DnsDomainName>
> 
> For the PDCs the query is _ldap._tcp.pdc._msdcs.<DnsDomainName>. host or dig
> should be able to do the work.
> 
> You can find more information from the google search engine with "Windows
> 2000 DNS".
> 
> Hope this can help.
> 
> Elia
> 
> 
> 
> -----Messaggio originale-----
> Da: Richard Sharpe [mailto:rsharpe at ns.aus.com]
> Inviato: venerdì 3 maggio 2002 5.24
> A: samba-technical at samba.org
> Oggetto: Heuristics for finding a Win2K domain controller ...
> 
> 
> Hi,
> 
> Does anyone know any heuristics for finding a Win2K Domain controller?
> 
> WINS does not seem to work the same way as NT4 ...
>  
> Regards
> -----
> Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, 
> sharpe at ethereal.com
> 
> 

-- 
Regards
-----
Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, 
sharpe at ethereal.com