On Mon, 2017-03-13 at 17:49 +0100, Andy Smith wrote: > I can see that the domain in question does have A and MX records, > possibly issues are that the A record doesn't match the PTR for the > IP returned by the A record and that one of the MX records doesn't > have a PTR. I'd be keen to know if one or both of these are the > issue, and what the situation WRT RFCs on email DNS says about what > are required for proper operation of email. > Does the domain have a PTR record for every A record and, by extension, for every MX record? You should be able to check this with 'dig' or simply use 'host' to verify that the relevant reverse lookups work OK.
Is the domain's SPF record valid and configured properly? I use this site for checking SPF records: http://www.kitterman.com/spf/validate.html Martin
