I have installed 2 Exchange servers, both with the mailbox and cas role. My goal is to use both servers regularly instead of having one just for backup. I have setup a dag and even though not the best, using DNS rr to provide access to both servers. In testing to see what we need to know if a server goes down or needs maintenance, I have manually shutdown each server one at a time and checked to see that I still had access to everything.
Lets call the servers M1 and M2. So I first shutdown M2 and access to M1 remained the same for everything you can think of (outlook, owa, ecp, etc). Then I brought M2 backup and checked on status again and everything worked ok. But once I shutdown M1 and left M2 up, I could no longer access any resource. owa and ecp would not work and Outlook lost connection to Exchange.
In order to make sure that I was not accessing M1 since I have DNS rr, I manually set outlook to M2 address and tried to access OWA and ECP by accessing M2 address but that did not work.
Can anyone tell me what is going on?