So I am going to be installing a second 2013 Exchange server in a secondary site that will have both Mail and CAS roles, same as the first. I plan to create a DAG between these two sites and have it so that if one server goes down the other can pick up the mail and deliver. Is there a walkthrough or a high level overview on how to get this accomplished. I know I will need to do the following:
1. Install exg2013
2. Create DAG and witness server.
3. Have MX record point to new server (is there any firewall rules I need to put in place? any tech net article?)
4. Have our ISP DNS servers point "mail.company.org" point to both servers.
I know I am probably missing a ton, but this is a work in progress and I am gathering my information before I begin.