> On Dec 8, 2016, at 14:57, Dominic Raferd <domi...@timedicer.co.uk> wrote:
>
> Thanks for your swift reply Dusan. What you write is logical but my postfix
> doesn't seem to behave that way. I have no special setting for
> maximal_queue_lifetime but I give below a recent extract from my log
> (obfuscated). After trying both gmail hosts and being pushed away with 421
> 4.7.0 it goes straight to the fallback relay ('relay.gridlock.net') with
> delay <=1s. This particular server has no relayhost set (but I see the same
> behaviour on another server which has).
This is expected because smtp_fallback_relay behaves just like the additional
lowest preference MX, meaning 4xx retries are spread over all MX (including
smtp_fallback_relay), however 5xx is not retried and is a bounce.
