diff -ur linux-2.4.19-rc3-ac3-mppe-netfilter-htb-noreplace/include/linux/netfilter_ipv4/ipt_string.h linux-2.4.19-rc3-ac3-mppe-netfilter-htb/include/linux/netfilter_ipv4/ipt_string.h
--- linux-2.4.19-rc3-ac3-mppe-netfilter-htb-noreplace/include/linux/netfilter_ipv4/ipt_string.h	Tue Oct  1 02:20:32 2002
+++ linux-2.4.19-rc3-ac3-mppe-netfilter-htb/include/linux/netfilter_ipv4/ipt_string.h	Tue Oct  1 23:44:00 2002
@@ -14,8 +14,10 @@
 
 struct ipt_string_info {
     char string[BM_MAX_NLEN];
+		char replace[BM_MAX_NLEN];
     u_int16_t invert;
     u_int16_t len;
+		u_int16_t replace_len;
 };
 
 #endif /* _IPT_STRING_H */
diff -ur linux-2.4.19-rc3-ac3-mppe-netfilter-htb-noreplace/net/ipv4/netfilter/ipt_string.c linux-2.4.19-rc3-ac3-mppe-netfilter-htb/net/ipv4/netfilter/ipt_string.c
--- linux-2.4.19-rc3-ac3-mppe-netfilter-htb-noreplace/net/ipv4/netfilter/ipt_string.c	Thu Jul 25 20:38:15 2002
+++ linux-2.4.19-rc3-ac3-mppe-netfilter-htb/net/ipv4/netfilter/ipt_string.c	Wed Oct  2 01:01:50 2002
@@ -21,7 +21,10 @@
 #include <linux/module.h>
 #include <linux/skbuff.h>
 #include <linux/file.h>
+#include <linux/ip.h>
 #include <net/sock.h>
+#include <net/checksum.h>
+#include <net/tcp.h>
 
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv4/ipt_string.h>
@@ -110,7 +113,7 @@
 	const struct ipt_string_info *info = matchinfo;
 	struct iphdr *ip = skb->nh.iph;
 	int hlen, nlen;
-	char *needle, *haystack;
+	char *needle, *haystack, *result;
 	proc_ipt_search search=search_linear;
 
 	if ( !ip ) return 0;
@@ -137,7 +140,22 @@
 		}
 	}
 	
-    return ((search(needle, haystack, nlen, hlen)!=NULL) ^ info->invert);
+	if ((result = search(needle, haystack, nlen, hlen)) != NULL &&
+		info->replace_len > 0) {
+			struct tcphdr *tcph = (void *)ip + ip->ihl*4;
+		  u_int32_t tcplen = skb->len - ip->ihl*4;
+		  u_int32_t datalen = tcplen - tcph->doff*4;
+
+			memcpy (result, info->replace, min (info->len, info->replace_len));
+
+		  skb->csum = csum_partial((char *)tcph + tcph->doff*4, datalen, 0);
+		  tcph->check = 0;
+		  tcph->check = tcp_v4_check(tcph, tcplen, ip->saddr, ip->daddr,
+				csum_partial((char *)tcph, tcph->doff*4, skb->csum));
+			ip_send_check(ip);
+	}
+
+  return ((result != NULL) ^ info->invert);
 }
 
 static int