Guido,

I'm not sure but something tells me the AD domain is not used yet. Is this
true?
Is CORP.COMPANY.COM the forest root?

What about the following:

(1) (somewhat a big bang)
* Create an additional BDC for NT4 corp domain
* Isolate the additional BDC from NT4 corp domain
* Promote the additional BDC to PDC and rename the domain to something else
(e.g. NT4CORP)
* Connect to the PDC from NT4CORP to AD CORP (trusts, etc.)
* Migrate all users, groups and memberships
* Disconnect PDC from NT4CORP
* Rejoin all servers/clients to AD CORP domain (not sure how exchange likes
this)
* Re-acl

(2)
If the AD CORP domain is not used yet, are there reason to destroy the AD
CORP domain and do and in-place upgrade of the NT4 CORP domain to AD.
Upgrading only the PDC and from there introduce new W2K3 DCs and remove the
old ones. This wat they keep the CORP name, no re-acling including all the
other default migration issues. Afterwards only cleanup and configure the AD
domain (OUs, delegation, sites, etc.) as soon as possible

Cheers
#JORGE#

-----Original Message-----
From: [EMAIL PROTECTED]
To: [email protected]
Sent: 6/16/2005 10:12 PM
Subject: RE: [ActiveDir] Migration between domains with same NetBios name

Hey Jorge, 
 
thanks for your thoughts - you missed that I'm not going to register the
AD DCs in WINS, so that's not an issue. It's having them in the same
subnet is what I'm slightly worried about and need to check if it's even
possible. 
 
Messing with the old domain name is not an option either (don't forget
it's production until fully migrated...). And not much time to do it
either...
 
The interimdomain scenario was another one going through my head (yes -
indeed similar to my DEC session ;-) - but I'm trying to avoid it here
as I know what's involved...  And it bugs me that they "just" have the
same names - MS definitely needs to come up with something like
"domain-name aliases" (and I think they're even working on this). But
I'll definitely leave the interimdomain/forest option on my list if I
get the deal (still bid phase).  And definitely a good topic for next
DEC (just kidding - I'd say migrations are getting somewhat boring... -
however, not one is the same as another...)
 
Cheers,
Guido

  _____  

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jorge de
Almeida Pinto
Sent: Donnerstag, 16. Juni 2005 16:08
To: [email protected]
Subject: RE: [ActiveDir] Migration between domains with same NetBios
name


Hi Guido, 
 
NetBIOS based domains/clients find domain controllers through the WINS
record 1Ch. If two different domains share the same WINS infrastructure
I think both domain's DCs wil register in the same record and then you
will have some interesting troubleshooting to do. Don't forget that most
migration tools use the browser service to enumerate several objects..
again tricky.
As allready said renaming the source domain is a possibility (however
I'm not sure if E55 likes domain renames). For this you need to
inventory all places that use THE NAME OLDOMAIN in user accounts. One of
the examples are the logon account for services. I'm sure there more. To
do this you are stuck to a "major step moment"
 
Another possibility is to use an interim domain which I think gives you
the possibility to do a phase migration. You will me migrating twice
though.
 
MIGRATION SCENARIO:
* OLDDOMAIN -> INTERIMDOMAIN | NEWDOMAIN
* OLDDOMAIN | INTERIMDOMAIN -> NEWDOMAIN
 
INTERIMDOMAIN migration - quick and dirty steps
* Pre-install and configure (isolated) NEWDOMAIN, its DNS, its DHCP, its
WINS, etc. and shutdown afterwards
* 2 DCs (W2K3 AD) for interim
* Exch55. in the same org as exch. in OLDOMAIN
* Migrate servers, clients, users, groups, mailboxes,etc. from OLDDOMAIN
to INTERIMDOMAIN
* Configure INTERIMDOMAIN SERVERS to use WINS infrastructure from
OLDDOMAIN
* Configure INTERIMDOMAIN CLIENTS to use DHCP infrastructure from
OLDDOMAIN
* Decommission old exchange in OLDOMAIN
* Shutdown old domain
* Bring up NEWDOMAIN
* Reconfigure servers and clients to use WINS and DHCP from NEWDOMAIN
* Install exch2k3 in NEWDOMAIN
* Migrate servers, clients, users, groups, mailboxes,etc. from
INTERIMDOMAIN to NEWDOMAIN 
 
etc.etc.
 
What do you think abou this one?
 
Cheers
#JORGE#
 
I think almost the same scenario as the situation you presented during
DEC "Handling_Mergers_and_Acquistions". Let me guess your next
presentation at DEC will be "Migrations between domains with the same
NetBIOS name"? ;-))
 
Whatever scenario you choose will be painfull. You must however think
about the scenarion to use that is less painfull

  _____  

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Grillenmeier,
Guido
Sent: Thursday, June 16, 2005 09:53
To: [email protected]
Subject: RE: [ActiveDir] Migration between domains with same NetBios
name


Thanks Eric, renaming the source NT4 domain was on the list of my
options and I know that it works as I've done it before in a larger
test-environment.  However, I expect many more headaches in a production
environment as it's difficult to analyse all the dependencies to
existing apps, e.g. Exchange 5.5 and others. 
 
And since you need to re-join all members to the domain anyways, it's
almost as much work as just joining them to the target domain...
 
...hmm - that just triggered a thought - I guess it would be possible to
do just that: rename the source dom (on PDC) + re-join all BDCs, then
setup trust to the target domain and join all resources to target domain
while accounts & groups are still in (renamed) source domain. [thinking
continues]... ofcourse the challenges with the apps and potential
dependencies on the old domain name remain and need to be analysed first
- so it's really tough to estimate the amount of work involved for
this...
 
Besides, the obvious downside is fallback options => customers usually
don't allow any drastic changes in the existing infrastructure, when
migrating to another one - which I fully understand.
 
 
So I was mainly seeking for other experience and things to look out for,
if domain rename is not an option.  E.g. is it really an issue to have a
BDC of the NT4 CORP domain in the same subnet as a DC of the AD CORP
domain?  I guess I could hinder the AD DC somehow from trying to race
against the NT4 BDC to become master browser.  Even when we plan to do a
hard-cutover (long weekend), I'll need DCs of both domains available at
some point...  And I know I need to test this anyways, but can't do so
right now.
 
I should mention, that I'm talking about roughly 1000 users with clients
and servers distributed in a dozen locations. So nothing major - a hard
cutover should be doable over a long 4-day weekend (incl. migration of
all mailboxes at once) and handling re-ACLing on the FS is no issue.
 
Accrd. to customer, there are no other apps (other than Exchange) that
leverage the NT4 domain for anything (other than running on a
memberserver).  My past experience tells me that this is likely not to
be true...  I'm sure there are other things that are often overlooked -
any ideas?
 
/Guido

 
  _____  

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Fleischman
Sent: Donnerstag, 16. Juni 2005 07:53
To: [email protected]
Subject: RE: [ActiveDir] Migration between domains with same NetBios
name



Rename it?

 

I will admit, I've never actually tried this, but I know people who say
it works. I think you should try this procedure, on a test box first,
and report back. Maybe you should do it to an BDC you bring up just to
test, isolated, and see how it goes.

http://support.microsoft.com/default.aspx?scid=kb;en-us;169741
<http://support.microsoft.com/default.aspx?scid=kb;en-us;169741> 

 

If this does work, I'd like to know, so I can recommend it in the
future.

 

The other option is logical data migration but not actual "migration" if
you will. IE, ldifde and such. But that comes with the normal "lose the
SIDs" type of issues, which I assume to be a major headache for your
scenario.

 

~Eric

 

PS: Basically, this mail translates roughly in to me saying, this might
or might not work, and I'd like you to be my testing guy to let me know,
since I've never had occasion to give it a whirl myself.

 

 

  _____  

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Grillenmeier,
Guido
Sent: Wednesday, June 15, 2005 10:43 PM
To: [email protected]
Subject: [ActiveDir] Migration between domains with same NetBios name

 

Here is a nice one - I've done quite a few migration with all kinds of
scenarios, so I hardly ask questions around this topic. 

 

But when migrating from one NT4 domain to an AD domain which both have
the same NetBios names, various issues and potential conflicts come to
mind and I wonder if others had to do this in the past, who could share
their experience.

 

Think about an existing NT4 domain called CORP and another existing AD
domain called CORP (with DNS=copr.company.com). And now you need to
migrate all users and resources from the NT4 CORP to the AD CORP and
place AD DCs into the same sites as the exising NT4 DCs... 

 

I can imagine various challenges, besides not being able to setup a
trust and thus loosing various options for doing a "normal" migration.
At least I have no need to register the AD domain in WINS; all clients
are XP, but I know for sure that I'm going to run into various other
issues (the worst one being that the account activation and the resource
migration has to happend instantaneously, since resource access won't be
possible accross the domains). But I'm also thinking of networking
issues with and NT4 DC of the one and an AD DC of the other domain in
the same ip-subnet...

 

I wonder how others have tackled this challenge and what issues you ran
into. 

 

/Guido



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