diff --git a/fastrpc.cgi b/fastrpc.cgi
index 4c0e885ea..e570125e5 100755
--- a/fastrpc.cgi
+++ b/fastrpc.cgi
@@ -349,8 +349,8 @@ if ($fh6) {
 	}
 while(1) {
 	$$port++;
-	if ($$port >= 65536) {
-		return "Failed to allocate a free port!";
+	if ($$port < 0 || $$port > 65535) {
+		return "Failed to allocate a free port number: $port";
 		}
 	$pack = pack_sockaddr_in($$port, INADDR_ANY);
 	next if (!bind($fh, $pack));