[exim] Backupserver

Hi!

I want to setup an exim-enabled backup mailserver.

Could somebody please explain me how to config of the backupserver should be?

- So, hoew does Exim knows it is a backupserver for the domains?
- What should the retry time be, for the backupserver to deliver the mail to the primairy mailserver?
- Could, or should, I use smtpauth?
- What other things should I do?

Cheers,

Hub