diff --git a/extensions/libxt_pknock.c b/extensions/libxt_pknock.c
index 581e5bb..3e671a9 100644
--- a/extensions/libxt_pknock.c
+++ b/extensions/libxt_pknock.c
@@ -296,7 +296,7 @@ static void pknock_print(const void *ip,
 		printf(" ");
 	}
 	if (info->option & IPT_PKNOCK_TIME)
-		printf("time %ld ", info->max_time);
+		printf("time %ld ", (long)info->max_time);
 	if (info->option & IPT_PKNOCK_NAME)
 		printf("name %s ", info->rule_name);
 	if (info->option & IPT_PKNOCK_OPENSECRET)
@@ -318,7 +318,7 @@ static void pknock_save(const void *ip, const struct xt_entry_match *match)
 		printf(" ");
 	}
 	if (info->option & IPT_PKNOCK_TIME)
-		printf("--time %ld ", info->max_time);
+		printf("--time %ld ", (long)info->max_time);
 	if (info->option & IPT_PKNOCK_NAME)
 		printf("--name %s ", info->rule_name);
 	if (info->option & IPT_PKNOCK_OPENSECRET)
diff --git a/extensions/xt_pknock.h b/extensions/xt_pknock.h
index 171b34f..a798edb 100644
--- a/extensions/xt_pknock.h
+++ b/extensions/xt_pknock.h
@@ -29,15 +29,15 @@
 
 struct ipt_pknock {
 	char		rule_name[IPT_PKNOCK_MAX_BUF_LEN + 1];
-	int			rule_name_len;
+	uint32_t			rule_name_len;
 	char		open_secret[IPT_PKNOCK_MAX_PASSWD_LEN + 1];
-	int			open_secret_len;
+	uint32_t			open_secret_len;
 	char		close_secret[IPT_PKNOCK_MAX_PASSWD_LEN + 1];
-	int			close_secret_len;
+	uint32_t			close_secret_len;
 	uint8_t	option;		/* --time, --knock-port, ... */
 	uint8_t	ports_count;	/* number of ports */
 	uint16_t	port[IPT_PKNOCK_MAX_PORTS]; /* port[,port,port,...] */
-	unsigned long	max_time;	/* max matching time between ports */
+	uint32_t	max_time;	/* max matching time between ports */
 };
 
 struct ipt_pknock_nl_msg {