Well, as promised this is the time for posting something new about the exchange server installations. I am focusing majorly on exchange server 2003 installation however I have also tried to shed some light on exchange server 2007 installation too.
Continuing the old story one more time this post covers up the below:
- Preparation of Active Directory Schema, Configuration and Domain naming contexts.
- Installation of software prerequisites.
- Installation of Exchange Server binary files.
Preparation of Active Directory Schema, Configuration and Domain naming contexts.
As all we know exchange is a very tightly integrated application with active directory and dies without it there are some preparations required in active directory so that it can accommodate the exchange as a service in it. Let’s take a look at what are they. Preparing active directory mainly consists of preparation of active directory forest so that the very first exchange server can be installed in it and the domain preparation. Forest preparation is required only once in the entire AD forest however the domain preparation is always domain specific i.e. if you have 10 different domains in the same root forest you really don’t need the forest preparation to be run several times however for every exchange server installation in any of these 10 domain you need to run the domain preparation.
Now the question is what happens when forest preparation is run and how to do it. All those who have already installed exchange may be familiar with forest preparation but those who have not done this ever will have a good idea of it now.
Running Forest Preparation (setup.exe /ForestPrep)
The exchange installation CD is shipped with an autorun program which launches an HTA and facilitates running forestprep from the interface itself however I prefer to run it from Start> Run every time. If the contents of the installation CD are browsed you can easily get to the location Drive:setupi386 setup where the actual installer is located and its off course setup.exe. To learn more about installing exchange server you can also refer http://technet.microsoft.com/en-us/library/bb124186(EXCHG.65).aspx its as easy as any other installation program on windows.
So, when setup.exe is launched using a switch /forestprep it tries to contact the Schema Master role of Active Directory automatically as it has to write some classes and definitions into the schema so that the newly inserted classes can be used to store in the user specific information in Domain Naming Context and the configuration specific information in Configuration Naming Context. If you open the schemamgmt.msc tool and take a look the normal schema which is not extended by any other application you will some predefined classes beginning from ms-DS-…. Unlike these Exchange ForestPrep defines its own schema classes, extensions, attributes which begin from ms-Exch-…… These schema extensions are used by Exchange Server to store, co relate and retrieve the information from Active Directory. Microsoft has very wisely used the Active Directory database to store the Exchange Server information in it. Exchange Server 5.x versions used to have their own Directory database for storing this information in it. This used be named as dir.edb, another LDAP compliant architecture. However this database was not an object oriented database as Active Directory and used to have its own mechanism to store the information in it.
Once the setup program finishes inserting the new schema extensions into the Schema Naming Context it moves to the configuration naming context and binds to it. It then locates the Services container in configuration naming context and creates another object in it name “Microsoft Exchange” this container is the one which stores information about the Exchange Organization configuration. The best view can be seen using adsiedit.msc. Once the creation of Exchange Organization in AD is complete it also creates the organization wide accessible and impacting containers in it. They are namely, Address Lists, Global Settings and etc, etc yet they are not accessible and visible to the end user (unless Exchange system management tools are already installed). Unlike any other enterprise application Exchange also needs an administrator account which will be administering it. This account is an exchange full administrator. Whenever the setup launches ForestPrep is prompts to enter an Active Directory account which will be used to install exchange in the forest. This is administrator account by default however this can be changed to any other account having at least a Schema Admin group membership J nothing left huh?