currently, my config does include
smtpd_helo_required = yes
smtpd_helo_restrictions =
permit_mynetworks
check_helo_access pcre:${config_directory}/helo_access.pcre
reject_invalid_helo_hostname
reject_non_fqdn_helo_hostname
permitis adding to head of helo_access.pcre /.*\.outbound\.protection\.outlook\.com/ OK sane/safe?
