> On Dec 8, 2016, at 08:39, Dominic Raferd <domi...@timedicer.co.uk> wrote: > > 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).
With or without smtp_fallback_relay, 4xx temporary failure is retried for maximal_queue_lifetime = 5d (default), while 5xx permanent failure is bounced immediately.
