#!!# ACL that is used after the RCPT command on the submission port
check_submission:
+ # Accept if the source is local SMTP (i.e. not over TCP/IP).
+ # We do this by testing for an empty sending host field.
+ accept hosts = : 127.0.0.1
# Defer after too many bad RCPT TO's. Legit MTAs will retry later.
# This is a rough pass at preventing addres harvesting or other mail blasts.