diff -urN /usr/ports/mail/milter-greylist/Makefile milter-greylist/Makefile
--- /usr/ports/mail/milter-greylist/Makefile	2017-01-18 23:25:55.000000000 +0300
+++ milter-greylist/Makefile	2017-07-11 04:07:16.294636000 +0300
@@ -30,12 +30,14 @@
 # installed port preference over it.
 ##
 
-OPTIONS_DEFINE=		SPF GEOIP CURL LDAP P0F POSTFIX DOCS EXAMPLES
+OPTIONS_DEFINE=		DKIM SPF GEOIP CURL LDAP P0F POSTFIX DOCS EXAMPLES
+DKIM_DESC=		DKIM support
 SPF_DESC=		SPF support
 CURL_DESC=		curl support
 P0F_DESC=		P0F support
 POSTFIX_DESC=		Use Postfix instead of Sendmail
 
+DKIM_LIB_DEPENDS=	libopendkim.so:mail/opendkim
 P0F_RUN_DEPENDS=	p0f:net-mgmt/p0f
 SPF_LIB_DEPENDS=	libspf2.so:mail/libspf2
 CURL_LIB_DEPENDS=	libcurl.so:ftp/curl
@@ -47,6 +49,8 @@
 
 P0F_CONFIGURE_ENABLE=		p0f306
 
+DKIM_CONFIGURE_ON=		--with-libopendkim=${LOCALBASE}
+DKIM_USES=			ssl
 SPF_CONFIGURE_ON=		--with-libspf2=${LOCALBASE}
 GEOIP_CONFIGURE_ON=		--with-libGeoIP=${LOCALBASE}
 CURL_CONFIGURE_ON=		--with-libcurl=${LOCALBASE}