Exchange 2010 Namespace considerations

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

  • – MX Record, mail flow
  •, OWA, OMA, EAS, (Web Services) – Certificate Name

This is not always the case, some people will just use 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, – Primary point of presence, OWA, OA, EAS, OAB – Certificate Name

Auto discover Service

  • – auto configuration URL– Certificate Name

Client Access Arrays

  • – Internal AD reference to CAS Array for each site
  • – Internal AD reference to CAS Array for each site
  • – Assigned to VIP of Load balancer for HA CAS – Certificate Name
  • – Assigned to VIP of Load balancer for HA CAS – Certificate Name


  • – Name used for redirection to 2003 during migration – Certificate Name

Site Resiliency

  • – alternate internet pointe of presence– Certificate Name

Failback URLs

  • – DNS Failback URL for timeout consideration – Certificate Name
  • – 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

Forefront Unified Access Gateway 2010, what’s that then?

I keep hearing a lot of confusion as to what UAG is, where it fits, and what it does, so here is a brief introduction to what it does, and what it’s capabilities are.
Forefront Unified Access Gateway 2010 is designed as a gateway into your organization, and utilizes a number of other Microsoft components to enable a seamless and integrated experience for both corporate users, and 3rd parties

  • UAG is NOT the same as TMG, nor are the two interchangeable
  • UAG is geared toward securely allowing inbound access
  • TMG is geared toward protecting internal users from external threats

A lot of confusion arises because UAG installs some TMG components and utilizes them, mainly for array management and firewalling, it cannot however operate as a forward or reverse proxy, nor can it do web filtering or use the active protection components that TMG does

The TMG components built into UAG are there to protect the TMG server, as it is generally afforded a global external address and does not sit behind its own firewall due to the NAT restrictions if you wish to utilize DirectAccess

Direct Access

Microsoft DirectAccess technology allows you to bridge the connections of enterprise endpoints to the corporate network whenever they are online, this is accomplished seamlessly and securely with a combination of IPv6, PKI and IPSEC technologies.  This allows users to access resources on the corporate infrastructure safely from anywhere they can get online, as well as providing internal support staff access to roaming systems without requiring them to join special support sessions, install special software, or have the user bring the system into an office

DirectAccess is a technology built into Windows 2008 R2, and can operate without UAG, however there are significant benefits to deploying direct access through a UAG system, including DNS64 and NAT64, both of which are required to allow seamless network access to IPv4 only corporate resources (not just IPv6 ready apps)

Remote Access

UAG provides a user web portal to access applications, services and network resources, as well as integrating with an RDS gateway component if you chose to install that, this portal provides access to numerous devices and can detect the type of device, and the type of experience to deliver.  These portals can be customized to fit the clients needs, to display client assets and specifics on a case by case basis

UAG is also capable of VPN termination, this can be via integration with RRAS for PPTN and SSTP tunnels, or via native UAG SSL VPN capabilities

While TMG can also do VPNs, it is not afforded the same SSL VPN capabilities that UAG has, this is another UAG plus point

Server Publishing

UAG is the Microsoft recommendation for publishing Microsoft server resources, this is a shift from IAG2007 when MS still pushed ISA2006 as it’s best practice method for securing Exchange and SharePoint web interfaces.  If you wish to make services such as outlook web access, outlook anywhere, active sync and SharePoint sites available to your users over the internet, this is the technology to deploy to secure and manage access to those resources.

TMG can still handle this, but many of the upgrades and features that have been added to UAG2010 have not been included in TMGs publishing capabilities, so when publishing SharePoint, Exchange, or even RDS Web Access, UAG is the way to go (reverse proxy requirements are still handled by TMG 2010, this includes OCS and Lync requirements)


UAG has client and server CAL requirements, unlike TMG which is licensed as a server (unless you want all the filtering and protection suites), however ECALS have UAG CALs included, this is good to know for ECAL customers as the majority of the cost is already paid for and you can start benefiting from the technology straight away through a pilot, or implementation engagement