diff --git a/ngrep.c b/ngrep.c
index c2a8aa9..ff676a4 100644
--- a/ngrep.c
+++ b/ngrep.c
@@ -108,7 +108,7 @@ uint32_t snaplen = 65535, limitlen = 65535, promisc = 1, to = 100;
 uint32_t match_after = 0, keep_matching = 0, matches = 0, max_matches = 0;
 
 #if USE_TCPKILL
-uint16_t tcpkill_active = 0;
+uint32_t tcpkill_active = 0;
 #endif
 
 uint8_t  re_match_word = 0, re_ignore_case = 0, re_multiline_match = 1;
@@ -337,7 +337,7 @@ int main(int argc, char **argv) {
                 break;
 #if USE_TCPKILL
             case 'K':
-                tcpkill_active = atoi(optarg);
+                tcpkill_active = _atoui32(optarg);
                 break;
 #endif
             case 'h':
diff --git a/tcpkill.c b/tcpkill.c
index 2363224..5388ec5 100644
--- a/tcpkill.c
+++ b/tcpkill.c
@@ -23,13 +23,12 @@ libnet_t *l;
 
 void
 tcpkill_kill(const struct pcap_pkthdr *pcap, const u_char *pkt,
-       unsigned pcap_off, unsigned kill_count)
+       uint32_t pcap_off, uint32_t kill_count)
 {
   struct libnet_ipv4_hdr *ip;
   struct libnet_tcp_hdr *tcp;
   u_char ctext[64];
-  u_int32_t seq, win;
-  int i, len;
+  uint32_t seq, win, i, len;
 
   pkt += pcap_off;
   len = pcap->caplen - pcap_off;
diff --git a/tcpkill.h b/tcpkill.h
index 32328dd..497ab2f 100644
--- a/tcpkill.h
+++ b/tcpkill.h
@@ -2,6 +2,6 @@
 #define TCPKILL_H
 
 void tcpkill_init(void);
-void tcpkill_kill(const struct pcap_pkthdr *pcap, const u_char *pkt, unsigned pcap_off, unsigned kill_count);
+void tcpkill_kill(const struct pcap_pkthdr *pcap, const u_char *pkt, uint32_t pcap_off, uint32_t kill_count);
 
 #endif