--- 1.17/check_rcpt.conf	2018-05-24 00:30:05.000000000 -0500
+++ 1.18/check_rcpt.conf	2018-05-25 17:28:03.000000000 -0500
@@ -11,6 +11,7 @@
        set acl_m_spam_domain = $domain
 
   warn
+       !authenticated = *
        condition = ${if !eq{$acl_m_esf_skip}{1}}
        hosts    = !+relay_hosts
        domains  = !+skip_rbl_domains