[Samba] LDAP master-slave and BDC ?

Msdigital mark at msdigitaldzines.com
Fri May 20 14:02:24 GMT 2005

Thank you for the explanation. It is clear to me now. Your last comment is 
interesting. If the PDC is the weakest link, what are the other alternatives 
that are strong links?

 By fail-over I mean if the authentication server fails or is down, my user 
would still be able to login and use the workstation.


----- Original Message ----- 
From: "John H Terpstra" <jht at Samba.Org>
To: <samba at lists.samba.org>; "Msdigital" <mark at msdigitaldzines.com>
Sent: Thursday, May 19, 2005 8:09 PM
Subject: Re: [Samba] LDAP master-slave and BDC ?

> On Thursday 19 May 2005 20:04, Msdigital wrote:
>> I am a bit confused, about the LDAP master-slave and BDC. I have an
>> Samba-LDAP server that serves as my PDC. All my users authenticate to 
>> this
>> server. I would like to set up a BDC for failover. What is the difference
>> between a BDC and a LDAP Slave server?
> A BDC is a NT4 domain controller that handles network logon 
> authentication.
> A Samba BDC will relay all network account updates to a PDC. Only the PDC 
> will
> write to the passdb backend. A BDC will read authentication data from the
> passdb backend it is configured to use.
> A Slave LDAP server is a read-only mirror of an LDAP Master server. A PDC
> would normally be directed at a Master LDAP server, but can work with a 
> Slave
> LDAP server. If a PDC is configured to use a Slave LDAP server all write
> requests to the directory will be handled via a referral to the Master 
> server. In other words, all write requests are handled by the Master LDAP
> server.
> It does not matter whether a BDC uses a Master or a Slave LDAP server - it
> only ever reads directory information from it.
> What do you mean by fail-over? A BDC can handle network logon requests, 
> but it
> can never replace a PDC. In other words, the PDC is still the weakest 
> link.
> If a PDC is off the air for a prolonged outage the network will eventually
> fail.
>> Second part.
>> Does anyone on this list have this type of configuration, PDC-BDC or
>> Master/Slave and can help do the same?
> Please refer to the book: "Samba-3 by Example" Chapters 5 and 6. You can
> obtain a copy from:
> http://www.samba.org/samba/docs/Samba-Guide.pdf
> Enjoy.
> - John T.
> -- 
> John H Terpstra
> Samba-Team Member
> Phone: +1 (650) 580-8668
> Author:
> The Official Samba-3 HOWTO & Reference Guide, ISBN: 0131453556
> Samba-3 by Example, ISBN: 0131472216
> Hardening Linux, ISBN: 0072254971
> Other books in production.

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