I just migrated from two 2007 servers to 2013.
One domain, different cities, Server2 is connected to the main Server1 by openVPN
Server1 is SP1
Server2 is CU10
Both are multirole.
There is a firewall at the edge of Server1 domain, which has public IP, where is MX record redirected to.
Server2 hasn't got any public IP
As I'm not much familiar configuring Exchange servers, I've had a lot of problems.
Emails from Server1 were going through slow (ADSL with realy bad upload) Server2
I "solved" it by disabling all receive conectors on Server2.
Emails sent by Server2 where stucking in draft folder, so I tried to change DNS lookup. I set the public IP as external and IP of the Server1's location DC as internal.
So the current problem is that if users which has mailboxes behind Server1 open Outlook clients (07,10,13) it sometimes redirects them to Server2. It happens almost every time they open outlook. Server1, than Server2 and so on...
There are default certificates, no autodiscover record in DNS, 'cause I don't know how exactly to configure autodiscover right.
If you want to see a screenshot, feel free to tell me.