I currently have 2 mail servers running on 2 different isp's, with 2 different outside ip addresses. They are located on the same network and I am able to connect the two so that they share settings, email, etc. I want to setup a load balance/failover situation where if one goes down the end client doesn't notice a change. I have read and am under the impression that this can be done through round robin dns and mx record priority. I understand how this will allow other email servers to connect to mine for email transport but my question is how will the end user be affected?
For example, if I setup my clients to use get.email.com for their incoming and outgoing servers and have get.email.com dns records point to my two outside ip addresses, what will happen if one of my servers goes down? Will it try the other ip in the dns record? In other words how will the email client behave if the first ip address that is resolved is down?