[...] acl_smtp_rcpt = acl_check_rcpt acl_smtp_data = acl_check_data [...] begin acl acl_check_rcpt: warn set acl_m0 = 0 accept hosts = : accept hosts = +auth_relay_hosts condition = ${if eq {$interface_port}{587} {yes}{no}} endpass message = relay not permitted, authentication required authenticated = * deny message = Restricted characters in address domains = +local_domains local_parts = ^[.] : ^.*[@%!/|]