--- gross-1.0rc4/src/worker.c.orig	2008-04-28 13:17:49.000000000 +0800
+++ gross-1.0rc4/src/worker.c	2008-04-30 18:43:01.000000000 +0800
@@ -187,6 +187,49 @@
 }
 
 int
+check_helo(char *helo)
+{
+	int match_dot = 0;
+	int match_bad = 0;
+	int match_isalpha = 0;
+	int match_isnum = 0;
+//	int match_bracket = 0;
+	char *ptr = helo, *tmp = helo;
+	int ret = 0;
+	char c;
+
+	while (tmp && (c = tmp++[0]))
+		if (c == '/')
+			ptr = tmp;
+
+	while (ptr && (c = ptr++[0])) {
+		if (c == '-' || (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')) {
+			match_isalpha++;
+			continue;
+		} else if (c >= '0' && c<= '9') {
+			match_isnum++;
+			continue;
+		} else if (c == '.') {
+			match_dot++;
+			continue;
+//		} else if (c == '[' || c == ']') {
+//			match_bracket++;
+//			continue;
+		} else if (c == '_') {
+			continue;
+		} else {
+			match_bad++;
+			break;
+		}
+	}
+	if (match_dot == 3 && match_isnum >= 4 && match_isalpha == 0)
+		ret = 0;
+	else if (match_dot > 0 && match_bad == 0 && match_isnum + match_isalpha >= 2)
+		ret = -1;
+	return ret;
+}
+
+int
 test_tuple(final_status_t *final, grey_tuple_t *request, tmout_action_t *ta)
 {
 	char maskedtuple[MSGSZ];
@@ -265,6 +308,8 @@
 	} else if (0 == checkcount) {
 		/* traditional greylister */
 		retvalue = STATUS_GREY;
+	} else if (0 == check_helo(request->helo_name)) {
+		retvalue = STATUS_GREY;
 	} else {
 		/* build default entry, if timeout not given */
 		if (!ta) {