For some of us, migrating from Exchange 2003 to Exchange 2010 is an exciting concept, with tons of new features, simpler high-availability features and a lot more power for the users
One of the common overlooked design pieces of a Microsoft Exchange 2010 architecture is the namespace considerations
Legacy Environments
for most Exchange 2003 environments the following names are usually in play
- mail.mydomain.com – MX Record, mail flow
- webmail.mydomain.com, OWA, OMA, EAS, (Web Services) – Certificate Name
This is not always the case, some people will just use mail.mydomain.com for everything, and this also works great. Your edge configuration will apply certain requirements/restrictions on how you configure your existing namespace, but this is all relatively simple in Exchange 2003 compared to some of the considerations in Exchange 2010.
Exchange 2010
Most organizations are deploying Exchange 2010 in a highly available configuration, and many are implementing site resilient considerations also, this can lead to a complex namespace design that should be carefully considered and design before the first server is deployed in your organization.
Some things to consider in Exchange 2010 from a high availability standpoint are
Internet Presence
- webmail,mydomain.com – Primary point of presence, OWA, OA, EAS, OAB – Certificate Name
Auto discover Service
- autodiscover.mydomain.com – auto configuration URL– Certificate Name
Client Access Arrays
- site-casA.mydomain.com – Internal AD reference to CAS Array for each site
- site-casB.mydomain.com – Internal AD reference to CAS Array for each site
- casA-nlb.mydomain.com – Assigned to VIP of Load balancer for HA CAS – Certificate Name
- casB-nlb.mydomain.com – Assigned to VIP of Load balancer for HA CAS – Certificate Name
Co-Existence
- legacy.mydomain.com – Name used for redirection to 2003 during migration – Certificate Name
Site Resiliency
- webmail2.mydomain.com – alternate internet pointe of presence– Certificate Name
Failback URLs
- failbackA.mydomain.com – DNS Failback URL for timeout consideration – Certificate Name
- failbackB.mydomain.com – DNS Failback URL for timeout consideration – Certificate Name
As you can see there is a lot to consider here before jumping in and throwing some servers up, and some of these names may not be required, or can be consolidated with others depending on your edge topology
For more detailed information on namespace design please check out the TechNet article located here