Bypass Postfix 'reject_unknown_client_hostname' for authenticated SMTP clients

tcdaly asked:

In my postfix configuration, I’ve switched on smtpd_client_restrictions = reject_unknown_client_hostname as an anti-spam measure.

However, sometimes I fall foul of this myself when I make an authenticated SMTP connection to the server from remote hosts that don’t have reverse DNS. My attempt to send an email gets rejected.

Is there any way to ignore smtpd_client_restrictions = reject_unknown_client_hostname in the case of an authenticated client?

My answer:


You just need to permit authenticated clients, for instance:

smtpd_client_restrictions = 
        permit_sasl_authenticated,
        reject_unknown_client_hostname,
        #...the rest of them

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