A Nice Domain\Forest Question

BF2Mad

Hi,

Not totally Cert related but I need some help with this question.

If I have two domains in the same forest, with 1 domain controller for each domain I understand that the Global Catalogue gets replicated to all domain controllers in a forest (correct me if I am wrong)

My question is with the above set-up as the same global catalogue sits on both Domain Controller will either domain controller be able to deal with requests for both domains?

So if one of the domain controller goes down will both domains will still function.

Obviously in a production environment you would have more than one domain controller for each domain

Thanks
Phil

strauchr

The Global Catalogue is only replicated to Domain Controllers marked as a Global Catalogue Server (set in AD Sites and Services)

You need at least one GC in each domain which is by default the first Domain Controller in a domain. In your setup all DCs will be a GC.

While the Global catalogue holds information for the entire forest users will not be able to authenticate to a domain that has no Domain Controllers running (in theory).

If you have the opportunity this would be a good experiment to try and run to see what happens but officially the domain without a DC should not function, regardless of a GC.

BF2Mad

Thanks for the reply.

I think you are right, the only way to make sure is to give it a test.

I will try this out on and let you know.

Does anyone else have anything to add?

BF2Mad

What is there was a two way trust between the domains? do you think that would make a difference

sprkymrk

In AD all domains in the same forest have an automatic transitive trust (2-way). Someone please correct me if I am wrong... :

TeKniques

Just thought I would suggest here that it is best to have at least 2 DC's in each site.

sprkymrk wrote:

In AD all domains in the same forest have an automatic transitive trust (2-way). Someone please correct me if I am wrong

That is correct. Two-way transitive trust I believe.

Lee H

Hi

some info on what exam i would be studying to gain all knowledge surrounding this question, i only have a very basic understanding of multi domain transitive trusts

Lee H

BF2Mad

I have not got that far yet but I would guess 70-297 (MCSE) would cover this subject

MCSE guys is that correct?

eurotrash

Or the 294.

evanderburg

The GC alone would not be enough to authenticate for another domain. It contains forest information but not at the level that a domain does. It contains more sparse information.

BF2Mad

Hi,

Thanks Guys!!

I have since tested (and read everything ) and found the same, while the Global Catalogue is replicated to all DC's in a forest it does not contain enough information.

As a least one active DC is required per domain for users to be authenicated to that domain.

2 way trusts are auto setup between domains in the same forest.

How about this then.

Can DHCP servers load balance? I know with 2003 Advance server you can cluster a couple of server but is there another way to add redundancy if you have 2 DHCP servers and one goes down?

I have read about the 80/20 rule but cannot get my head around it and how that would add redundancy or load balancing. Can anyone explain???

sprkymrk

In the NT4 days the rule was something like 70/30 or 60/40. In other words, set up your scope on a primary DHCP server and include 60-70% of your addresses on this server, which is hopefully almost enough to cover the whole network. then you set up a second DHCP server with the remaining 30-40% of your addresses. The theory was that if either one failed, the other server would have enough addresses to assign any expired leases until you could get the primary server back up and running.

BF2Mad

Ok,

From what I have read both DHCP server have the same scope but with IP address's excluded from the scope. e.g.

DHCP Server 1
Scope: 192.168.1.40 to 192.168.1.254
Exclude: 192.168.1.130 to 192.168.1.254

DHCP Server 2
Scope: 192.168.1.40 to 192.168.1.254
Exclude: 192.168.1.40 to 192.168.1.130

The ratio is wrong but is that the idea?

If DHCP Server 1 falls over how does DHCP Server 2 take over DHCP Server 1 IP's, is automatic or a manual thing?

(full of questions today)

Thanks again

BF2Mad

BINGO

Its has just clicked, I get it now.

Thanks