diff --git a/ChangeLog b/ChangeLog
index 7c9f79e5875b7151e0a4dd3d3e0e7d4fd449aa4a..e0af7c0af96cf804d1232410e8c577518ae487d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -447,4 +447,5 @@
 	* Add support to uIP for application access to ICMP protocol stacks; Add
 	  ping request logic.
 	* NSH: Add ping command
+	* Correct IP checksum calculation in ICMP and UDP message send logic.
 
diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index f05fdc6ce906a9128867114e955b534b682ca89c..06169e4ea0cba3c15053d536a3aaf2c1888d942d 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: September 2, 2008</p>
+      <p>Last Updated: September 3, 2008</p>
     </td>
   </tr>
 </table>
@@ -1074,6 +1074,7 @@ nuttx-0.3.14 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 	* Add support to uIP for application access to ICMP protocol stacks; Add
 	  ping request logic.
 	* NSH: Add ping command
+	* Correct IP checksum calculation in ICMP and UDP message send logic.
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/net/uip/uip-icmpsend.c b/net/uip/uip-icmpsend.c
index c0076b0e8c865ec33b25b06cebc3b3207491b2d5..fc8ac2e8355a8f828cc21466b42a462fa49f7b0a 100644
--- a/net/uip/uip-icmpsend.c
+++ b/net/uip/uip-icmpsend.c
@@ -92,7 +92,7 @@ void uip_icmpsend(struct uip_driver_s *dev, uip_ipaddr_t *destaddr)
 {
   if (dev->d_sndlen > 0)
     {
-      /* The total lenth to send is the size of the application data plus
+      /* The total length to send is the size of the application data plus
        * the IP and ICMP headers (and, eventually, the ethernet header)
        */
 
@@ -130,19 +130,19 @@ void uip_icmpsend(struct uip_driver_s *dev, uip_ipaddr_t *destaddr)
       ++g_ipid;
       ICMPBUF->ipid[0]     = g_ipid >> 8;
       ICMPBUF->ipid[1]     = g_ipid & 0xff;
-      ICMPBUF->ipoffset[0] = 0;
-      ICMPBUF->ipoffset[1] = 0;
+      ICMPBUF->ipoffset[0] = UIP_TCPFLAG_DONTFRAG >> 8;
+      ICMPBUF->ipoffset[1] = UIP_TCPFLAG_DONTFRAG & 0xff;
       ICMPBUF->ttl         = UIP_TTL;
       ICMPBUF->proto       = UIP_PROTO_ICMP;
 
+      uiphdr_ipaddr_copy(ICMPBUF->srcipaddr, &dev->d_ipaddr);
+      uiphdr_ipaddr_copy(ICMPBUF->destipaddr, destaddr);
+
       /* Calculate IP checksum. */
 
       ICMPBUF->ipchksum    = 0;
       ICMPBUF->ipchksum    = ~(uip_ipchksum(dev));
 
-      uiphdr_ipaddr_copy(ICMPBUF->srcipaddr, &dev->d_ipaddr);
-      uiphdr_ipaddr_copy(ICMPBUF->destipaddr, destaddr);
-
 #endif /* CONFIG_NET_IPv6 */
 
       /* Calculate the ICMP checksum. */
diff --git a/net/uip/uip-udpsend.c b/net/uip/uip-udpsend.c
index 563d31a8175b3d01204408c3e5c297b7f60b937b..79ab3685654dc5ff8217afcb3a1ad2adfb03071d 100644
--- a/net/uip/uip-udpsend.c
+++ b/net/uip/uip-udpsend.c
@@ -134,14 +134,14 @@ void uip_udpsend(struct uip_driver_s *dev, struct uip_udp_conn *conn)
       UDPBUF->ttl         = conn->ttl;
       UDPBUF->proto       = UIP_PROTO_UDP;
 
+      uiphdr_ipaddr_copy(UDPBUF->srcipaddr, &dev->d_ipaddr);
+      uiphdr_ipaddr_copy(UDPBUF->destipaddr, &conn->ripaddr);
+
       /* Calculate IP checksum. */
 
       UDPBUF->ipchksum    = 0;
       UDPBUF->ipchksum    = ~(uip_ipchksum(dev));
 
-      uiphdr_ipaddr_copy(UDPBUF->srcipaddr, &dev->d_ipaddr);
-      uiphdr_ipaddr_copy(UDPBUF->destipaddr, &conn->ripaddr);
-
 #endif /* CONFIG_NET_IPv6 */
 
       /* Initialize the UDP header */