diff -Naur knock-0.5-orig/src/knockd.c knock-0.5/src/knockd.c
--- knock-0.5-orig/src/knockd.c	2005-06-27 08:11:34 +0300
+++ knock-0.5/src/knockd.c	2008-11-25 09:39:47 +0200
@@ -46,6 +46,7 @@
 #include <syslog.h>
 #include <pcap.h>
 #include <errno.h>
+#include <limits.h>
 #include "list.h"
 
 static char version[] = "0.5";