Exchange 2013 - How does Outlook Anywhere connect Externally

We have 2 sites, Prod and DR. We're doing a DR test externally from an ISP perspective, no Exchange DB or server failovers. All mailboxes are in Prod (site1). External access goes to which goes to prod. We will be repointing that DNS to the DR site, which points to the DR exchange server. Prod and DR Exchange servers (site1 and site2) are in the same DAG.

When outlook anywhere connects to the DR Exchange server, it will say your mailbox is on Exchange server in the other site, what will happen? Does it use the External URL? Will it loop?
Scotch TechITAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Bradley FoxLAN/WAN Systems AdministratorCommented:
You would want to set the external URL the same on both Prod and DR CAS servers.  When you have to failover you will need to change your DNS records to get users over to the DR site.  Change DNS for your OWA URL (likely something like  Set your autodiscover record as a CName and point at the OWA URL so all you have to change is the OWA (A) record.  Set the TTL on your OWA record to a low value, something like 300 seconds so the switch over is quick quick.
Scotch TechITAuthor Commented:
We only allow Outlook Anywhere, we block OWA. Is your instructions still valid then?
Bradley FoxLAN/WAN Systems AdministratorCommented:
Yes, the instructions still work without OWA.  Either way you are just trying to get the clients pointed at the DR CAS instead of the Prod CAS.  Basically, you need to have the same configuration on both systems and will manually fail them over by changing DNS.

I'm not sure what the circuits look like between the CAS servers so when you fail DNS over you may need to manually force the database to activate on the DR CAS as well.  This would only be the case if the internet was down at Prod site but the servers were still able to talk to each other.  You do this using ECP, Servers on the left, Database tab, select your database and you can activate it on the other server in the right pane.
Scotch TechITAuthor Commented:
But to confirm, we are not moving or failing over DB's they will remain on the Prod side, we just want Client access to come in via DR site, then internally Exchange to say " your mailbox is over in this site" and route over there.
Bradley FoxLAN/WAN Systems AdministratorCommented:
In that case you should just need to change your autodiscover record to point at the DR site, however, since this server is in the DAG why not activate the database on the DR server and decrease the traffic on your site to site circuit?  When you switch back to Prod, just force the database active at the prod site in EAC.

Since they are both in a DAG it will keep a fully replicated copy on each server.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.