Hi We have an Exchange Server 2013 environment which is deployed on 2 Sites.

Site A and Site B. Both Sites are connected via VPN.

We have 2 mailbox servers on each site. We have create a DAG all 4 mailbox server are member of that DAG. We have a third site which is on separate location and this site is also connected via vpn with both Sites as shown in the diagram.

The issue is that our databases were mounted on Mailbox 1 on Site A. Primary active manager was also on Mailbox A. VPN from site B to Site A was disconnected. Due to this our databases were dismounted and users faced disconnectivity. We were able to access Site B from  Site A but Single Site VPN tunnel was disconnected from Site B to Site A. Can anyone help us why our databases were dismounted.

In case our VPN tunnel from Third Site to Site A disconnects then how we can able to failover to Site B. We have DNS failover and if any of our CAS is not accessible then DNS automatically failover to next CAS server and OWA points to active CAS but our DAG does not failover. Can any body give us any opinion.

Any help will be highly appreciated.

Regards,

Anees

• Edited by AneesUrRehman Friday, July 10, 2015 3:43 PM correction

Ed Crowley,

Thanks for your reply. Our VPN tunnel is very reliable. The thing is that whenever there is any issue with Network connectivity of Site A or Site B, whole site goes down. In this case witness should play it's role and failover to other site. Unfortunately this is not happening in our case. Whenever our Site A goes down site B is not automatically up.Our databases goes down and if  we try to mount database forcefully on Site B we are getting the following error message:

Active Manager isn't reachable on server mbx1.SiteA.com. The Microsoft Exchange Replication service might not be running. Error Error 0x6ba (The RPC server is unavailable) from cli_GetPrimaryActiveManager.
    + CategoryInfo          : InvalidOperation: (ExchangeSite:ADObjectId) [Move-ActiveMailboxDatabase], InvalidOperationException
    + FullyQualifiedErrorId : [Server=MBX2,RequestId=22cee80d-6dbb-4d5a-b21f-84b90e27c1ce,TimeStamp=01/19/2014 5:19:50 AM] [FailureCategory=Cmdlet-InvalidOperationException] 1AAD809E,Microsoft.Exchange.Management.SystemConfigurationTasks.MoveActiveMailboxDatabase
    + PSComputerName        : mbx2.siteB.com

Thank you.

Anees