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Deleted
Feb 15, 2023

Exchange 2019 and IP-less DAG - how does failover work?

Hey all.   We currently have 2 Exchange 2013 servers (main and DR) in a DAG.  We have a DAG DNS A record with the IP address of the MAPI interface on our main Exchange server.  Our mail.ourdomain.c...
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Deleted

Hey sbohmer

Regarding our existing IP-full dag, failover clustering is set up to change the IP of the dag01.domain.com DNS A record. We have our primary namespace (client connectivity) mail.ourdomain.com as a CNAME pointing to dag01.ourdomain.com, and dag01.ourdomain.com A record has the IP of the main server MAPI interface.

mail.ourdomain.com(CNAME) => dag01.domain.com(A) => IP of main server MAPI interface

In the event of main server death or disablement (or patching) failover clustering automatically changes the IP address of the dag01.domain.com A record to our backup server.

mail.ourdomain.com(CNAME) => dag01.domain.com(A) => IP of backup server MAPI interface

Works fine for our needs. Just not sure how an ip-less dag would work in this situation.

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sbohmer
Copper Contributor
Mar 21, 2023
Deleted We currently have all internal mail related dns pointed to the DAG IP address. We thought the issue was related to an incorrect firewall setting but it turns out our second server somehow was configured with 2 gateways. Once the second gateway was removed and corrected all works as expected. Server1 goes down server2 takes over with no issues. We still have a single point of failure as we have a single Spamtitan that all mail comes through on the way in but it would take minutes for us to restore that if something were to happen to it. In regard to patching the host that sits on it takes a minute or less to move it to another host prior to reboots.
  • Deleted's avatar
    Deleted
    Mar 23, 2023
    We have something similar! MailScanner running on Linux that does our incoming spam/virus as well as outgoing dkim. Also single point of failure but...

    It would also take minutes to spin a backup of it's vm up, and it gets VRS'd to our remote site where the DR Exchange server sits.

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