Hello all,
Very recently we have received complaints of mail not functioning on one of our virtual servers. Upon investigation this seemed to be caused by GreyListing being enabled. When this is turned off mail functions normally in both directions.
However when this is turned on outgoing mail continues to function however incoming mail ceases to be delivered.
This is the postfix log with greylisting enabled (I have changed some of the names for privacy)
Feb 28 23:00:17 host01 postgrey[1991]: action=greylist, reason=new, client_name=mail-oln040092069063.outbound.protection.outlook.com, client_address=40.92.69.63, sender=testuser@outlook.com, recipient=user@domain.uk
Feb 28 23:00:17 host01 postfix/smtpd[20579]: NOQUEUE: reject: RCPT from mail-oln040092069063.outbound.protection.outlook.com[40.92.69.63]: 450 4.2.0 user@domain.uk: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/domain.uk.html; from=testuser@outlook.com to=user@domain.uk proto=ESMTP helo=<EUR02-VE1-obe.outbound.protection.outlook.com>
At the moment we have had to leave grey listing off to ensure mail is delivered but we don’t want to stay that way for long. Does anyone have any possible steps we can take to resolve this issue.
Thanks in advance