OK I admin I dont understand this (I will re-read the wiki version when I am less tired).
If I want to do things this way. Two Zimbra servers. Both with the same domain
both with separate mx records on higher priority than the other.
Main will normally go to mx1.mydomain.com but if this is busy or down it will go to mx2.mydomain.com.
Ideally I would like it if any mail gets into mx2.mydomain.com it would forward it to mx1.mydomain.com
However if mx1 fails completely (HD failure etc) a copy of all the mail is avaible on mx2.mydomain.com, in separate imap mailboxes.
This could be done with imapsync or similar.
So all I would need to do is set up the same accounts on each server.
The problem is that the mail getting to mx2 could not be forwarded to mx1 as they are both on the same domain mydomain.com
If I could forward
fred@mydomain.com to fred@213.160.23.123 where the IP address was the address of my primary server mx1 this would be OK.
Another suggestion I have seen is to set up another domain on the primary mail server so that the mail to
fred@mydomain.com thet gets to mx2 is forwarded to
fred@mx1.mydomain.com.
This would then have to go to
fred@mydomain.com in the primary server.
a copy could be sent to the local server.
Is this all silly?