We're using Postfix with Dovecot and SASL Auth via Dovecot (based on this tutorial). All works like expected. But when Dovecot is down (i.e. for maintenance or other reasons) then clients could not authenticate at Postfix and Postfix rejects client requests because of
smtpd_recipient_restrictions that follow after
Is there a ways to temporarily reject mails arriving at Postfix when Dovecot auth is down? Our postfix conf is:
smtpd_restriction_classes = check_sender_auth check_sender_auth = reject_authenticated_sender_login_mismatch, permit_sasl_authenticated, reject smtpd_recipient_restrictions = reject_invalid_helo_hostname, reject_non_fqdn_recipient, check_sender_access mysql:/etc/postfix/check_sender_domains, reject_non_fqdn_helo_hostname, [...]
check_sender_domains is a lookup table which return
check_sender_auth for sender address claiming to be from us.