On Thu December 3 2015 02:54:08 Michael Howard wrote:
> I'm now sorted, I added an exception to my mail server to allow emails
> from the list despite the rDNS failure. I'm considering turning the
> checks off completely as other valid mails are being rejected too. It's
> a trade off between spending half my time adding exceptions or receiving
> extra spam.

rDNS checks are run on the connecting IP, they are good at
stopping spam, and pearsoncomputing.net passes them.

SMTP HELO FCrDNS checks are bad.  mail.pearsoncomputing.net
currently fails them, Tim can easily fix that, but you'll
still run into problems with lots of other mail servers
and probably also with postmaster emergency communications
if you enable SMTP HELO FCrDNS checks.

I suggest that you enable rDNS checks and disable SMTP
HELO checks.

--Mike