We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you a podcast all about Citrix Workspace, moving to the cloud, and analytics & intelligence. Episode 2 coming soon!Listen Now


How do I make Exchange 2007 available on two different subnets?

Thukaung asked
Medium Priority
Last Modified: 2012-05-06
We have a single Exchange 2007 server in our main HQ office. The plan is to have our other branch offices added to the domain over existing VPN subnets to connect to the Exchange server. We're trying to add bandwidth to our Exchange server by hosting it on its own T1 line and creating a new subnet for it, and also keeping it available on the HQ subnet by using multiple NIC cards. Are there any issues we should be aware of, especially concerning DNS?
Watch Question

just ensure that the exchange server name resolution works through FQDN from both the networks. you do not have any settings in exchange to make it work on different IP Subnets. Just ensure these two networks can ping each other & the hosts can resolve the names correctly through nslookup


Another thing:

From the HQ office, the exchange server will appear as x.x.1.234. From external offices, the exchange server should appear as x.x.6.234. We plan on having DNS managed by Active Directory, replicated over the VPN links to DC's in each office. How do we have external offices resolve the server address differently than workstations at HQ office and keep it replicated over AD?
Expert of the Quarter 2009
Expert of the Year 2009

Dual homing Exchange is a bad idea, and not something I would recommend. Have the VPN links terminate on your existing LAN so that the clients can access the server on its own IP address. Don't forget the clients will also need to contact the domain controllers.




What are the drawbacks aside from this DNS issue? As far as I know, dual homing would be the best way to solve our bandwidth issues while keeping Exchange on the HQ LAN.
Expert of the Quarter 2009
Expert of the Year 2009
I and many other Exchange MVPs have just seen so many issues with dual homing, getting email to flow correctly, OWA not working reliably etc. It is just a mess.
I don't see how dual homing will resolve your bandwidth issues any more than just putting the server on the main LAN and having the VPN terminate on the LAN itself. If you are trying to use the connection exclusively for Exchange, then that simply isn't going to happen, as trying to segregate AD traffic in that way will usually cause a problem. To get the traffic to use that link will mean some AD changes will have to be made.


Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.