This way if your main mail server goes down, your mail will queue up on the second server specified in the MX dns record, and when the primary MX server comes on-line all the mail from the secondary MX will forward to the primary MX server when the server comes back on-line. mx 10 primary.server.com mx 20 secondary.server.com(this one would host the secondary domain that forward to the primary when it comes on-line) I'm sure there are more pressing things to add to ISPCONFIG, but it would be nice.
You do this normally with a mirror setup in ispconfig, just add 2 mail nodes in mirror mode to your multiserver install. This has the additional benefit that you can use the mirror also as failover imap server.
Yes but a mirror setup will mirror everything , not just that service. It would be great if we could control mirroring on a per service basis. With just two servers at the moment, it would be nice if they could just mirror dns and mail. I've gotten around the DNS part by creating secondary zones manually(in ISPCONFIG) for the secondary dns server, but there doesn't appear to be a workaround within ISPCONFIG for the mail. It will have to be done with a manual config in postfix, I guess.
