diff --git a/p4app/controller.py b/p4app/controller.py
index 0669137..3db1087 100644
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -110,8 +110,7 @@ class L2Controller(object):
 
         self.controller.table_clear("v6_addresses")
         for v6addr in self.v6_addresses[self.mode]:
-            self.controller.table_add("v6_addresses", "icmp6_answer", [v6addr['addr']], [v6addr['port']])
-
+            self.controller.table_add("v6_addresses", "icmp6_answer", [v6addr['addr']])
 
 
     def config_hosts(self):
@@ -133,6 +132,14 @@ class L2Controller(object):
             # mx h$i "ip -6 route add default via 2001:db8:6::42"
 
         #for v4route in self.v4_routes[self.mode]:
+        # Todo: add v4 routes / ip addresses
+
+        # Fake mac addresses - this gets REALLY messy now
+        # for host in range(4):
+        #     macrange = [1, 2, 3, 4, 42]
+
+        #     for mac in macrange:
+        #         subprocess.call(["mx", host, "ip", "addr", "add", ipaddr, "dev", dev])
 
 
     def debug_print_pkg(self, pkg, msg="INCOMING"):
diff --git a/p4app/static-mapping.sh b/p4app/static-mapping.sh
index d6d50f8..12fc862 100644
--- a/p4app/static-mapping.sh
+++ b/p4app/static-mapping.sh
@@ -17,7 +17,8 @@ for i in 1 2; do
 
     # add neighbors
     for j in 1 2 42; do
-        mx h$i "ip -6 neigh add 2001:db8:6::${j} dev $dev lladdr 00:00:0a:00:00:0${j}"
+        mx h$i "ip -6 neigh add 2001:db8:61::${j} dev $dev lladdr 00:00:0a:00:00:0${j}"
+        mx h$i "ip -6 neigh add 2001:db8:62::${j} dev $dev lladdr 00:00:0a:00:00:0${j}"
     done
 done
 
diff --git a/p4src/checksums.p4 b/p4src/checksums.p4
index b202b43..5c58803 100644
--- a/p4src/checksums.p4
+++ b/p4src/checksums.p4
@@ -21,6 +21,38 @@ control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
 
 control MyComputeChecksum(inout headers  hdr, inout metadata meta) {
     apply {
+        /* 512 bit+ according to
+        https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_checksum_for_IPv4
+        */
+			update_checksum_with_payload(
+			hdr.ipv6.isValid(),
+			{
+                hdr.ipv6.src_addr, /* 128 */
+				hdr.ipv6.dst_addr, /* 128 */
+				meta.tcpLength,
+				24w0,
+				hdr.ipv6.next_header,
+				// TCP header
+				hdr.tcp.src_port,
+				hdr.tcp.dst_port,
+				hdr.tcp.seqNo,
+				hdr.tcp.ackNo,
+				hdr.tcp.data_offset,
+				hdr.tcp.res,
+				hdr.tcp.cwr,
+				hdr.tcp.ece,
+				hdr.tcp.urg,
+				hdr.tcp.ack,
+				hdr.tcp.psh,
+				hdr.tcp.rst,
+				hdr.tcp.syn,
+				hdr.tcp.fin,
+				hdr.tcp.window,
+				hdr.tcp.urgentPtr
+			},
+			hdr.tcp.checksum,
+			HashAlgorithm.csum16);
+
     }
 }
 
diff --git a/p4src/headers.p4 b/p4src/headers.p4
index ca65fd2..5c28e1a 100644
--- a/p4src/headers.p4
+++ b/p4src/headers.p4
@@ -21,6 +21,9 @@ const bit<8>  PROTO_ICMP6  = 58;
 
 const bit<8>  TCP_SEQ_LEN = 4;
 
+const bit<8>  ICMP6_ECHO_REQUEST = 128;
+const bit<8>  ICMP6_ECHO_REPLY   = 129;
+
 
 header ethernet_t {
     mac_addr_t dst_addr;
diff --git a/p4src/static-mapping.p4 b/p4src/static-mapping.p4
index 629a137..64d8e73 100644
--- a/p4src/static-mapping.p4
+++ b/p4src/static-mapping.p4
@@ -17,7 +17,17 @@ control MyIngress(inout headers hdr,
     inout standard_metadata_t standard_metadata) {
 
     /********************** ADDRESS TABLES ***********************************/
-    action icmp6_answer(port_t port) {
+    action icmp6_answer() {
+
+        if(hdr.icmp6.isValid()) {
+            if(hdr.icmp6.code == ICMP6_ECHO_REQUEST) {
+                ipv6_addr_t tmp = hdr.ipv6.src_addr;
+                hdr.ipv6.src_addr = hdr.ipv6.dst_addr;
+                hdr.ipv6.dst_addr = tmp;
+                hdr.icmp6.code = ICMP6_ECHO_REPLY;
+            }
+        }
+
         /* do something:
         - change src/dst
         - change type
@@ -27,6 +37,7 @@ control MyIngress(inout headers hdr,
     table v6_addresses {
         key = {
             hdr.ipv6.dst_addr: exact;
+//            hdr.ipv6.next_header: exact;
         }
         actions = {
 			icmp6_answer;