diff --git a/datapath-windows/ovsext/DpInternal.h b/datapath-windows/ovsext/DpInternal.h
index 8de48a2..0405b8e 100644
--- a/datapath-windows/ovsext/DpInternal.h
+++ b/datapath-windows/ovsext/DpInternal.h
@@ -65,6 +65,8 @@ typedef struct _OVS_VPORT_EXT_INFO {
 typedef struct L4Key {
     ovs_be16 tpSrc;              /* TCP/UDP/SCTP source port. */
     ovs_be16 tpDst;              /* TCP/UDP/SCTP destination port. */
+    ovs_be16 flags;              /* TCP flags */
+    uint8_t  pad[2];
 } L4Key;
 
 typedef struct Ipkey {
@@ -75,7 +77,7 @@ typedef struct Ipkey {
     uint8_t nwTtl;               /* IP TTL/Hop Limit. */
     uint8_t nwFrag;              /* FLOW_FRAG_* flags. */
     L4Key   l4;
-} IpKey;  /* Size of 16 byte. */
+} IpKey;  /* Size of 20 byte. */
 
 typedef struct ArpKey {
     ovs_be32 nwSrc;              /* IPv4 source address. */
@@ -95,7 +97,6 @@ typedef struct Ipv6Key {
     uint8_t nwTtl;               /* IP TTL/Hop Limit. */
     uint8_t nwFrag;              /* FLOW_FRAG_* flags. */
     L4Key  l4;
-    uint32_t pad;
 } Ipv6Key;  /* Size of 48 byte. */
 
 typedef struct Icmp6Key {
@@ -110,7 +111,7 @@ typedef struct Icmp6Key {
     uint8_t arpSha[6];           /* ARP/ND source hardware address. */
     uint8_t arpTha[6];           /* ARP/ND target hardware address. */
     struct in6_addr ndTarget;    /* IPv6 neighbor discovery (ND) target. */
-} Icmp6Key; /* Size of 72 byte. */
+} Icmp6Key; /* Size of 76 byte. */
 
 typedef struct L2Key {
     uint32_t inPort;             /* Port number of input port. */
diff --git a/datapath-windows/ovsext/Flow.c b/datapath-windows/ovsext/Flow.c
index b629c93..ca6a353 100644
--- a/datapath-windows/ovsext/Flow.c
+++ b/datapath-windows/ovsext/Flow.c
@@ -980,6 +980,7 @@ _MapFlowIpv4KeyToNlKey(PNL_BUFFER nlBuf, IpKey *ipv4FlowPutKey)
     switch (ipv4Key.ipv4_proto) {
         case IPPROTO_TCP: {
             struct ovs_key_tcp tcpKey;
+            UINT16 tcpFlags = 0;
             tcpKey.tcp_src = ipv4FlowPutKey->l4.tpSrc;
             tcpKey.tcp_dst = ipv4FlowPutKey->l4.tpDst;
             if (!NlMsgPutTailUnspec(nlBuf, OVS_KEY_ATTR_TCP,
@@ -988,6 +989,13 @@ _MapFlowIpv4KeyToNlKey(PNL_BUFFER nlBuf, IpKey *ipv4FlowPutKey)
                 rc = STATUS_UNSUCCESSFUL;
                 goto done;
             }
+            tcpFlags = ipv4FlowPutKey->l4.flags;
+            if (!NlMsgPutTailUnspec(nlBuf, OVS_KEY_ATTR_TCP_FLAGS,
+                                   (PCHAR)(&tcpFlags),
+                                    sizeof(tcpFlags))) {
+                rc = STATUS_UNSUCCESSFUL;
+                goto done;
+            }
             break;
         }
 
@@ -1074,6 +1082,7 @@ _MapFlowIpv6KeyToNlKey(PNL_BUFFER nlBuf, Ipv6Key *ipv6FlowPutKey,
     switch (ipv6Key.ipv6_proto) {
         case IPPROTO_TCP: {
             struct ovs_key_tcp tcpKey;
+            UINT16 tcpFlags = 0;
             tcpKey.tcp_src = ipv6FlowPutKey->l4.tpSrc;
             tcpKey.tcp_dst = ipv6FlowPutKey->l4.tpDst;
             if (!NlMsgPutTailUnspec(nlBuf, OVS_KEY_ATTR_TCP,
@@ -1082,6 +1091,13 @@ _MapFlowIpv6KeyToNlKey(PNL_BUFFER nlBuf, Ipv6Key *ipv6FlowPutKey,
                 rc = STATUS_UNSUCCESSFUL;
                 goto done;
             }
+            tcpFlags = ipv6FlowPutKey->l4.flags;
+            if (!NlMsgPutTailUnspec(nlBuf, OVS_KEY_ATTR_TCP_FLAGS,
+                                   (PCHAR)(&tcpFlags),
+                                   sizeof(tcpFlags))) {
+                rc = STATUS_UNSUCCESSFUL;
+                goto done;
+            }
             break;
         }
 
@@ -1357,6 +1373,12 @@ _MapKeyAttrToFlowPut(PNL_ATTR *keyAttrs,
                 ipv4FlowPutKey->l4.tpDst = tcpKey->tcp_dst;
             }
 
+            if (keyAttrs[OVS_KEY_ATTR_TCP_FLAGS]) {
+                const UINT16 *flags;
+                flags = NlAttrGet(keyAttrs[OVS_KEY_ATTR_TCP_FLAGS]);
+                ipv4FlowPutKey->l4.flags = *flags;
+            }
+
             if (keyAttrs[OVS_KEY_ATTR_UDP]) {
                 const struct ovs_key_udp *udpKey;
                 udpKey = NlAttrGet(keyAttrs[OVS_KEY_ATTR_UDP]);
@@ -1401,6 +1423,12 @@ _MapKeyAttrToFlowPut(PNL_ATTR *keyAttrs,
                 ipv6FlowPutKey->l4.tpDst = tcpKey->tcp_dst;
             }
 
+            if (keyAttrs[OVS_KEY_ATTR_TCP_FLAGS]) {
+                const UINT16 *flags;
+                flags = NlAttrGet(keyAttrs[OVS_KEY_ATTR_TCP_FLAGS]);
+                ipv6FlowPutKey->l4.flags = *flags;
+            }
+
             if (keyAttrs[OVS_KEY_ATTR_UDP]) {
                 const struct ovs_key_udp *udpKey;
                 udpKey = NlAttrGet(keyAttrs[OVS_KEY_ATTR_UDP]);
@@ -1443,8 +1471,6 @@ _MapKeyAttrToFlowPut(PNL_ATTR *keyAttrs,
 
                 destKey->l2.keyLen += OVS_IPV6_KEY_SIZE;
             }
-
-            ipv6FlowPutKey->pad = 0;
         }
         break;
     }
@@ -1465,9 +1491,6 @@ _MapKeyAttrToFlowPut(PNL_ATTR *keyAttrs,
             /* Kernel datapath assumes 'arpFlowPutKey->nwProto' to be in host
              * order. */
             arpFlowPutKey->nwProto = (UINT8)ntohs((arpKey->arp_op));
-            arpFlowPutKey->pad[0] = 0;
-            arpFlowPutKey->pad[1] = 0;
-            arpFlowPutKey->pad[2] = 0;
             destKey->l2.keyLen += OVS_ARP_KEY_SIZE;
             break;
         }
@@ -1635,7 +1658,7 @@ OvsFlowUsed(OvsFlow *flow,
     flow->used = tickCount.QuadPart * ovsTimeIncrementPerTick;
     flow->packetCount++;
     flow->byteCount += OvsPacketLenNBL(packet);
-    flow->tcpFlags |= OvsGetTcpFlags(packet, &flow->key, layers);
+    flow->tcpFlags |= OvsGetTcpFlags(packet, layers);
 }
 
 
@@ -1796,6 +1819,7 @@ OvsExtractFlow(const NET_BUFFER_LIST *packet,
             ipKey->nwTtl = nh->ttl;
             ipKey->l4.tpSrc = 0;
             ipKey->l4.tpDst = 0;
+            ipKey->l4.flags = 0;
 
             if (!(nh->frag_off & htons(IP_OFFSET))) {
                 if (ipKey->nwProto == SOCKET_IPPROTO_TCP) {
@@ -1829,7 +1853,7 @@ OvsExtractFlow(const NET_BUFFER_LIST *packet,
         layers->isIPv6 = 1;
         flow->ipv6Key.l4.tpSrc = 0;
         flow->ipv6Key.l4.tpDst = 0;
-        flow->ipv6Key.pad = 0;
+        flow->ipv6Key.l4.flags = 0;
 
         if (flow->ipv6Key.nwProto == SOCKET_IPPROTO_TCP) {
             OvsParseTcp(packet, &(flow->ipv6Key.l4), layers);
@@ -1910,9 +1934,7 @@ AddFlow(OVS_DATAPATH *datapath, OvsFlow *flow)
      */
     KeMemoryBarrier();
 
-    //KeAcquireSpinLock(&FilterDeviceExtension->NblQueueLock, &oldIrql);
     InsertTailList(head, &flow->ListEntry);
-    //KeReleaseSpinLock(&FilterDeviceExtension->NblQueueLock, oldIrql);
 
     datapath->nFlows++;
 
diff --git a/datapath-windows/ovsext/Flow.h b/datapath-windows/ovsext/Flow.h
index e817bcf..5d74ca8 100644
--- a/datapath-windows/ovsext/Flow.h
+++ b/datapath-windows/ovsext/Flow.h
@@ -28,7 +28,7 @@ typedef struct _OvsFlow {
     OvsFlowKey key;
     UINT64 hash;
     UINT32 actionsLen;
-    UINT8 tcpFlags;
+    UINT8  tcpFlags;
     UINT64 used;
     UINT64 packetCount;
     UINT64 byteCount;
diff --git a/datapath-windows/ovsext/PacketParser.c b/datapath-windows/ovsext/PacketParser.c
index e01be17..219ddac 100644
--- a/datapath-windows/ovsext/PacketParser.c
+++ b/datapath-windows/ovsext/PacketParser.c
@@ -186,6 +186,7 @@ OvsParseTcp(const NET_BUFFER_LIST *packet,
     if (tcp) {
         flow->tpSrc = tcp->source;
         flow->tpDst = tcp->dest;
+        flow->flags = OvsGetTcpFlags(packet, layers);
         layers->isTcp = 1;
         layers->l7Offset = layers->l4Offset + 4 * tcp->doff;
     }
diff --git a/datapath-windows/ovsext/PacketParser.h b/datapath-windows/ovsext/PacketParser.h
index 55d110f..765819a 100644
--- a/datapath-windows/ovsext/PacketParser.h
+++ b/datapath-windows/ovsext/PacketParser.h
@@ -75,11 +75,8 @@ OvsGetTcpCtl(const NET_BUFFER_LIST *packet, // IN
 
 static UINT8
 OvsGetTcpFlags(const NET_BUFFER_LIST *packet,    // IN
-               const OvsFlowKey *key,   // IN
                const POVS_PACKET_HDR_INFO layers) // IN
 {
-    UNREFERENCED_PARAMETER(key); // should be removed later
-
     if (layers->isTcp) {
         return TCP_FLAGS(OvsGetTcpCtl(packet, layers));
     } else {
