Automate Failover Testing Between Primary and Secondary Mail Servers
Having two MX hosts is not the same as knowing failover works. The only way to trust it is to test it: confirm both hosts answer on port 25 and accept mail for your domain, and once in a while prove that when the primary is down, the secondary still takes the message and holds it. This guide gives you a small probe script you can run on a schedule, and a controlled live drill for the real thing.
















































































