Is is better to install Exchange Server on a Domain Controller or a Member Server? The answer to this question has a lot of answers, for and against! Even with Exchange 2000, the question still remains. Everyone seems to have a different opinion, and even inside Microsoft, there is no definite for or against!

So what is the answer? Well lets look at the two biggest for and against arguments for this question.

Install on a Domain Controller!

As Exchange needs to authenticate clients, it is better to install on a domain controller to reduce the amount of time it takes to authenticate!

Install on a Member Server!

Exchange is an application, and does not need to be on a server that participates in domain replication.

The Answer!

Sorry to say this, but there is no real answer! The basic rule of thumb I use is this. If the Exchange server has a good high speed connection to the domain controller clients are using as their logon server, then install Exchange on a Member Server. If this is not the case, then install Exchange on a Domain Controller!

Personally, I prefer to install Exchange on a Member Server where possible! Network speeds these days are quite high, so the argument of installing Exchange on a Domain Controller only really comes into it, is the network speeds are slow. I don't feel that application servers should be on the same machines that participate in domain replication. It is an unnecessary task being required of the server.