I know we can set a secondary MX record that will take over the primary MX when the primary email server failed. The question is, when the primary email server is up, there will be email getting into the secondardy email server during the period the primary email server was down, so how do the email client download email from the secondary email server without having to amend their POP?
Not to mention that amending POP will lead to redownloading of all email again. Luckily Zimbra has the option to select download email from now on. A very useful feature.
How do you guys setup a backup email server when the primary failed? Do you use MX record with lower priority too?