I will be setting up exchange 2016 accross 2 sites. There will be 3 mailbox servers in both sites with 1 DAG (IP-Less DAG) that all mailbox servers will be members of. Site 1 will be production (hosting active copies of mailbox DBs) and all users will connect to this site, while site 2 will be only for DR failover (hosting passive copies of mailbox DBs). My question is in regards to client connectivity name spaces, I was wondering should i use the same client namespace for both sites or should site 1 have a namespace like prod.domain.com and site 2 have a namespace like DR.domain.com, or should there be just 1 single namespace for both such as mail.domain.com? I don't want to have the make any DNS changes if failover occur, and I only want the users connect to site 2 if there is a mailbox failover. The SSL can the single name space or both to ensure there are no certificate errors. What do you experts think is the best route. We have a netscaler load balancer that we will most likely use but I'm also thinking about DNS round robin for this since Exchange 2016 no longer support CASArray but it does support hardware load balancers and DNS Round Robin. Answer with DNS round robin is mind please and thanks.