Domain Topology and Exchange Server

We are planning on implementing Exchange Server 2003 onto our network, one of my work mates has been on an exchange server course and he feels that we have our domain topology setup wrong.

At the moment we have 7 separate domains each operating independently of each other. For example "“ domain1.local, domain2.local, domain3.local. All domains obviously have their own DC and they are all running Windows 2003 standard.

We have Two way trusts linking all the domains as well as DNS. Our DNS is configured to have Active Directory Integrated Primary forward lookup zones for the DC of that domain and then secondary forward lookup zones which point to every other domain.

Now I think that our topology is fine and that we can implement exchange onto it. My work mate thinks that we need to have one central DC e.g. central.local, then have each of our other domains as child domains of that e.g. domain1.central.local, domain2.central.local, domain3.central.local.

We are planning to put Exchange onto a server that does not have Active Directory Installed, I know that exchange has an active directory integrator thing, so it shouldn’t be a problem to connect to the other domains AD from the exchange server to set up mail boxes right?

So what do you guys think? Reconfiguring every domain would be a massive job that would cause so much disruption its not funny, we have about 200 users so I don’t really want to go down that road. And also if the central DC crashes then we loose the whole network. I cant see a problem with out current set up.

Any suggestions would be great! thanks

 

You can set up your domains anyway you want if it works for you.

Whether to have all the domains within a single forest (the domain.central.local model) or treat them as seperate domains depends to a large part on the network between them and the reliability of the links. If they are all on the same LAN (or CAN - fibre linked LANs in buildings in the same area/Campus) then the single forest is easier to manage as it will simplify the trust relationships. If they are on seperate LANs that communicate over WANs, there is some merit to keeping them seperate. Seperating them also makes you less suseptible to AD going titsup; a major AD problem isn't going to take down the whole network.

The other consideration is how users will authenticate with the mail server. If you aren't using AD to authenticate users, either will do. If you are looking to integrate the whole thing - the single forest probably has merit.

I am a great believer in the axim "if it ain't broke, don't fix it ". As you seem to be installing Exchange on its own, I'd leave the domains as they are, unless you hit a problem.

 

Our LANs are located all over the country, the WAN links are ok most of the time but we do have some problems with them dropping out for a period of time

 

Personally, if your current system works, I'd leave it as it is unless you come across a compelling reason to change it. It not being the most elegant implementation of the Microsoft architecture is not a compelling reason to change, in my opinion.