For those of you, like myself, who have “Reject message if the originating IP does not match HELO/EHLO declaration” enabled within Additional AntiSpam Methods you may currently be experiencing issues receiving emails from domains which use Yahoo SMTP servers (especially for UK based addresses / domains).
This is because Yahoo have email servers with the same FQDN on multiple IP addresses, thus potentially causing rDNS failures.
The example I have been seeing relate to the server sonic.asd.mail.yahoo.com which has recently been reporting numerous IP addresses, such as 74.6.128.82 or 74.6.130.121 - upon the rDNS check above taking place, these IPs will not resolve to sonic.asd.mail.yahoo.com, resulting in the email being rejected.
Luckily, working with Axigen, we have managed to develop a rule to resolve these issues, whilst still having “Reject message if the originating IP does not match HELO/EHLO declaration” enabled.
To create this rule, go to Acceptance & Routing > Advanced Settings
Create a new rule with the following settings:
i) Name = whatever you want
ii) Conditions =
ii-a) Select ALL of the conditions below
ii-b) Select Remote EHLO Host is sonic.asd.mail.yahoo.com
ii-c) Select SPF Result is = Pass
iii) Actions =
iii-a) Select SMTP Action is = Accept
iii-b) Insert something meaningful in Explanation
iiii) Save and enable the filter