--- sendmail/daemon.c	2008-11-13 16:32:52.000000000 +0100
+++ sendmail/daemon.c	2008-11-13 16:29:48.000000000 +0100
@@ -102,6 +102,10 @@
 
 static int	NDaemons = 0;			/* actual number of daemons */
 
+#ifdef ACCEPTFILTER
+int	HaveAcceptFilter = 0;		/* have accept filter */
+#endif /* ACCEPTFILTER */
+
 static time_t	NextDiskSpaceCheck = 0;
 
 /*
@@ -1046,6 +1050,9 @@
 {
 	int on = 1;
 	int fdflags;
+#ifdef ACCEPTFILTER
+	struct accept_filter_arg afa;
+#endif /* ACCEPTFILTER */
 	SOCKADDR_LEN_T socksize = 0;
 	int ntries = 0;
 	int save_errno;
@@ -1216,6 +1223,21 @@
 			(void) close(d->d_socket);
 			goto severe;
 		}
+#ifdef ACCEPTFILTER
+		if (!firsttime) {
+			errno = 0;
+			bzero(&afa, sizeof(afa));
+			strcpy(afa.af_name, "smtp prefilter");
+			strcpy(afa.af_arg, "");
+			if (setsockopt(d->d_socket, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa)) < 0)
+			    sm_syslog(LOG_ALERT, NOQID, "daemon %s: failed to set accept filter, error %s",
+				d->d_name, strerror(errno));
+			else {
+				HaveAcceptFilter = 1;
+				sm_syslog(LOG_ALERT, NOQID, "daemon %s: accept filter %s ready", d->d_name, afa.af_name);
+			}
+		}
+#endif /* ACCEPTFILTER */
 		return socksize;
 	} while (ntries++ < MAXOPENTRIES && transienterror(save_errno));
 	syserr("!opendaemonsocket: daemon %s: server SMTP socket wedged: exiting",
--- sendmail/srvrsmtp.c	2008-11-13 16:32:52.000000000 +0100
+++ sendmail/srvrsmtp.c	2008-11-13 16:28:40.000000000 +0100
@@ -108,6 +108,10 @@
 
 extern ENVELOPE	BlankEnvelope;
 
+#ifdef ACCEPTFILTER
+extern int HaveAcceptFilter;
+#endif /* ACCEPTFILTER */
+
 #define NBADRCPTS						\
 	do							\
 	{							\
@@ -1115,30 +1119,36 @@
 	id = strchr(inp, ' ');
 	if (id == NULL)
 		id = &inp[strlen(inp)];
-	if (p == NULL)
-		(void) sm_snprintf(cmdbuf, sizeof(cmdbuf),
-			 "%s %%.*s ESMTP%%s", greetcode);
-	else
-		(void) sm_snprintf(cmdbuf, sizeof(cmdbuf),
-			 "%s-%%.*s ESMTP%%s", greetcode);
-	message(cmdbuf, (int) (id - inp), inp, id);
+#ifdef ACCEPTFILTER
+	if (! HaveAcceptFilter) {
+#endif /* ACCEPTFILTER */
+		if (p == NULL)
+			(void) sm_snprintf(cmdbuf, sizeof(cmdbuf),
+				 "%s %%.*s ESMTP%%s", greetcode);
+		else
+			(void) sm_snprintf(cmdbuf, sizeof(cmdbuf),
+				 "%s-%%.*s ESMTP%%s", greetcode);
+		message(cmdbuf, (int) (id - inp), inp, id);
 
-	/* output remaining lines */
-	while ((id = p) != NULL && (p = strchr(id, '\n')) != NULL)
-	{
-		*p++ = '\0';
-		if (isascii(*id) && isspace(*id))
-			id++;
-		(void) sm_strlcpyn(cmdbuf, sizeof(cmdbuf), 2, greetcode, "-%s");
-		message(cmdbuf, id);
-	}
-	if (id != NULL)
-	{
-		if (isascii(*id) && isspace(*id))
-			id++;
-		(void) sm_strlcpyn(cmdbuf, sizeof(cmdbuf), 2, greetcode, " %s");
-		message(cmdbuf, id);
+		/* output remaining lines */
+		while ((id = p) != NULL && (p = strchr(id, '\n')) != NULL)
+		{
+			*p++ = '\0';
+			if (isascii(*id) && isspace(*id))
+				id++;
+			(void) sm_strlcpyn(cmdbuf, sizeof(cmdbuf), 2, greetcode, "-%s");
+			message(cmdbuf, id);
+		}
+		if (id != NULL)
+		{
+			if (isascii(*id) && isspace(*id))
+				id++;
+			(void) sm_strlcpyn(cmdbuf, sizeof(cmdbuf), 2, greetcode, " %s");
+			message(cmdbuf, id);
+		}
+#ifdef ACCEPTFILTER
 	}
+#endif /* ACCEPTFILTER */
 
 	protocol = NULL;
 	sendinghost = macvalue('s', e);