"Nigel J. Andrews" <nandrews@investsystems.co.uk> writes:
> Doesn't that just force the delivering system to send the spam through your
> secondary server?
A 500-series error isn't supposed to be retried is it? But in any case,
I run the same filters on my secondary server. Both the IP and the HELO
checks would be quite useless if I used an MX that wouldn't support 'em.
regards, tom lane