I'm using Postfix 3.1.0. If a message is rejected by an onward server
with a transient error message (e.g. 421-4.7.0 'temporarily rate
limited') then my postfix immediately tries any other specified MXs per
the recipient address and if these give the same response (as they tend
to) it immediately sends using the specified smtp_fallback_relay.
Is there a way to get it instead to try again, after a delay, to the
primary onward server(s) (whether the one specified as relayhost or, if
no relayhost is specified, the MXs per the recipient address), and only
if these fail again (or after n times) then fallback?
If nothing was specified as smtp_fallback_relay would it wait and try
again on a transient error or would it just give up immediately? If the
former, this would give me the behaviour I want but I really need to
have the fallback option too (in case of permanent errors, or transient
errors that don't go away).
Thanks for any help
Dominic
