I was giving it some thought and even though having a DAG you have some high availability I was not happy that if one of the exchange servers went down clients would not connect to the DB (it takes a while for them to establish connection).

I had a public name setup but decided to make the internal name same as the external one. I had one DNS record setup but created the same for my other exchange servers.

So to give you an example, if you had to test email AutoConfiguration on Outlook the RPC server would also point to a specific server. I wanted to change this to point to the external name so that I had some more high availability. A proper load balancer etc. would be ideal but where budgets are tight this is the next best option.

If you run the following command you will see what your Internal, External names are set to:

• Get-ClientAccessServer | Get-OutlookAnywhere | select identity,*hostname

Output:

Identity : MyServerRpc (Default Web Site)
ExternalHostname :
InternalHostname : myserver.domain.com

Now we can go and change the URL’s so that outlook will connect to the External Name:

• Get-OutlookAnywhere | Set-OutlookAnywhere -InternalHostname mail.domain.com -InternalClientsRequireSsl $false

So because I am not using a load balancer at all I will make use of DNS Round Robin. Run the following command from either from powershell or a command prompt and it should list all the servers resolving to that name mail.domain.com.

• Resolve-DnsName mail.domain.com

Once the change has been made, give it time to replicate across all your servers. I left mine for 1 hour. After that I tested and ran the AutoConfiguration from Outlook it was now showing the RPC Server as mail.domain.com which is what I wanted.

Hope it helps