autodiscover record RRS feed

  • Question

  • If point to primary site, when primary site down.

    Outlook can't connect to but 2nd site exchange CAS still alive.

    How can I handle case?

    The DNS is share same namespace, I can add 2nd site exchange CAS to the root DNS manager.

    2nd site is down when primary site DNS down and the network outage between 2 sites.

    Windows 2016 Geo DNS can't handle this scenario ?


    Sunday, September 1, 2019 1:40 PM


All replies

  • Hello, 

    Just wanted to share my knowledge for this question.Please let me know does this answer's your question.

    Autodiscover for External Client Connectivity : 

    You can check with your vendor who Manages your External DNS records.

    For Autodiscover connections from internet, Recently we have configured DNS level load balancing in cloud flare which will do the port level monitoring (443) by using it own probes.

    In in the cloud flare,we have configured autodiscover name space " " with two different Public IP address .The public IP address mapped with our production Site was defined as Primary and it always accepts autodiscover client connections from internet untill the port number 443 was listening for the exchange in production site.

    In case, if the Port number 443 for the production site public ip address is not listening due to any reason like Production firewall is down\ Production site down\Exchange server down\Exchange services is not up, then the Autodiscover client Connections from internet for the namespace will automatically failback to the Public ip address which is mapped to the Secondary site.

    Thanks & Regards S.Nithyanandham

    Sunday, September 1, 2019 4:42 PM
  • Hi ,

    Thank you for share the external DNS handle autodiscover method and we are using look like same solution.

    I'm question on internal autodiscover records for different site.


    Monday, September 2, 2019 1:46 AM
  • Hello, 

    Thank for your reply.

    Exchange 2013 CAS servers are capable enough to proxy the request to the respective MBX server which holds the mailbox in the different AD site.Lets discuss in detail.

    Assumed you have load balancer is in place, you can map the namespace to the both the load balancer's in primary and secondary site.Meaning when a outlook client attempt to resolve the namespace, it will obtain two different IP addresses in the round robin Fashion.Outlook Client will always connect to the First IP address. 

    If you lose the load balancer in your primary site, you simply turn it off (or maybe turn off the VIP) and repair or replace it. Clients that aren’t already using the VIP in the secondary datacenter will automatically fail over to the secondary VIP without any change of namespace, and without any change in DNS.  You no longer have to perform a Datacenter switchover.

    Exchange 2013 leverages an inbuilt namespace fault tolerance.As most of client-Access protocols are now HTTP-based (Outlook Web App,Outlook,Outlook Anywhere,Active Sync and so on),Clients have the capability of using multiple IP addresses and providing Automatic failover at the client side.

    You can see the entire details in the following link.Read the chapter Achieving site resilience.

    My Heartfelt thanks to Nuno Mota for this Detailed book.

    Thanks & Regards S.Nithyanandham

    Monday, September 2, 2019 5:28 AM