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

PINTO ELIA PINTO.ELIA at insedia.interbusiness.it
Fri May 3 01:44:02 GMT 2002

Try standard DNS query as follow.

A windows 2000 domain is represented by a DNS domain name. Each domain
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
would register the following records with DNS:

spiros.nt.egge.com.			A
_ldap._tcp.nt.egge.com.  		SRV 		0 0 389
_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:

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.


-----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 ...


Does anyone know any heuristics for finding a Win2K Domain controller?

WINS does not seem to work the same way as NT4 ...
Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, 
sharpe at ethereal.com

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