We are seeing a lot of email being rejected by postfix, some of which is legitimate email that should be delivered.
What I'm seeing from the maillog is logs such as the following;
NOQUEUE: reject: RCPT from unknown[Our IP Address]: 554 5.7.1 <Internal Email address>: Recipient address rejected: Access denied; from=<External Email Address> to=<Internal Email address> proto=ESMTP helo=<mail-pg0-f51.google.com>
We are seeing this repeatedly for different external domains. However the majority of mail is coming through ok.
I've been reading about editing main.cf postfix to change the line smtpd_recipient_restrictions = permit_mynetworks, reject_unauth_destination to permit_unauth_destination.
Please can someone explain what this will do and if it will solve my problem?