Good afternoon! We currently have an existing on-prem Exchange 2013 CU20 multi-site DAG, and are about to begin installation of Exchange 2016 CU10 servers for the purpose of first testing a new backup solution and then to begin a migration of our Exchange 2013 databases to Exchange 2016. My question at this point relates to the *local* DNS entries to use during the initial co-existence period.
Essentially, I know that the namespaces on the new Exchange 2016 server have to be set according to the existing namespace configurations of our existing Exchange 2013 environment. we've re-issued a new cert including the names of the new 2016 serves (two production plus one in-place archive server); I have that down and ready to bring up the first Exchagne 2016 server.
However, our DNS is currently configured round-robin: *local* DNS contains two records for mail.mycompany.com (126.96.36.199, 188.8.131.52; two existing 2013 DAG members) and two records for autodiscover.mycompany.com (184.108.40.206, 220.127.116.11; two existing 2013 DAG members). Once the 2016 is installed and rebooted the namespaces on it will be config'd identically to the existing 2013 environment. We are *not* planning to add another DNS entry for mail pointing at the new 2016 server until we build the production servers and get them running. However, do I need to build a new autodiscover record for the 2016 server so it can participate in the round-robin? I know that the 2016 will proxy-down to the 2013 servers, but I'm getting mixed information regarding whether autodiscover *must* be configured in DNS for the new co-existing 2016 server. I've heard that *all* autodiscover client requests need to come into the 2016 servers in this configuration of co-existence: is that done automatically by virtue of Exchange versions, or do I need an internal autodiscover DNS entry to make it happen? And does that new record participate in round-robin, and do I need to remove the *Existing* autodiscover records to PREVENT round-robin?
The production servers (the upcoming second and third 2016 servers) will have new DNS entries added for their IP addresses pointing to mail once they're built and ready to start participating in the migration, but this first archive server won't go into production until *after* the migration; we will be using it with a new live mailbox for testing, so it has to be live. Given that it won't be part of the migration plan, do I need to include a record in DNS for mail for it? I'm stuck on where in the build & migration process I need to add local autodiscover and mail records to *local* DNS.