How to make secondary mail server transfer to Primary Server?

[goden]

I have two servers installed ispconfig3, i have a problem of how to make secondary mail server transfer emails to Primary Server when primary server was down ?

[till]

Normally you use a shared filesystem for the /var/vmail directory for this as explained in the ispconfig mirroring guide. So there is no need to transfer any ameilas, as all emails are available on both servers automatically.

[goden]

Sorry, I mean that I have a backup mail server, When primary was down, How can I make backup server to take over the master server operation?
and how to transfer backup server emails to primary when it's fine ? thanks!

[Toucan]

One server must be the mirror of the other.

Like Till said, a shared filing system for the vmail directory shared between the two servers.

If the two servers are behind a router, when one is down you could redirect the external ip to the new internal ip.

Or you could maybe use multiple mx records if each server has it's own ext ip.

There are other scenarios that use a heart beat monitor setup.

Do you have a copy of the ispconfig manual? You may get more assistance if you have read the guide first and then ask question on that.