diff --git a/drivers/network/tcpip/include/ticonsts.h b/drivers/network/tcpip/include/ticonsts.h
index 6d86b6787d5..cf125d99b10 100644
--- a/drivers/network/tcpip/include/ticonsts.h
+++ b/drivers/network/tcpip/include/ticonsts.h
@@ -32,31 +32,7 @@
 #define TCPIP_PROTOCOL_NAME     L"Tcpip"
 #endif /* _NTTEST_ */
 
-/* TCP/UDP/RawIP IOCTL code definitions */
-
-#define FSCTL_TCP_BASE     FILE_DEVICE_NETWORK
-
-#define _TCP_CTL_CODE(Function, Method, Access) \
-    CTL_CODE(FSCTL_TCP_BASE, Function, Method, Access)
-
-#define IOCTL_TCP_QUERY_INFORMATION_EX \
-    _TCP_CTL_CODE(0, METHOD_NEITHER, FILE_ANY_ACCESS)
-
-#define IOCTL_TCP_SET_INFORMATION_EX \
-    _TCP_CTL_CODE(1, METHOD_BUFFERED, FILE_WRITE_ACCESS)
-
-#define IOCTL_SET_IP_ADDRESS \
-    _TCP_CTL_CODE(14, METHOD_BUFFERED, FILE_WRITE_ACCESS)
-
-#define IOCTL_DELETE_IP_ADDRESS \
-    _TCP_CTL_CODE(16, METHOD_BUFFERED, FILE_WRITE_ACCESS)
-
 /* Unique error values for log entries */
 #define TI_ERROR_DRIVERENTRY 0
 
-/* Internal status codes */
-#define IP_SUCCESS                 0x0000 /* Successful */
-#define IP_NO_RESOURCES            0x0001 /* Not enough free resources */
-#define IP_NO_ROUTE_TO_DESTINATION 0x0002 /* No route to destination */
-
 /* EOF */
diff --git a/sdk/lib/drivers/ip/network/loopback.c b/sdk/lib/drivers/ip/network/loopback.c
index e44cc69d3d7..c859ac7d2a8 100644
--- a/sdk/lib/drivers/ip/network/loopback.c
+++ b/sdk/lib/drivers/ip/network/loopback.c
@@ -36,7 +36,7 @@ VOID LoopTransmit(
  *   NdisPacket  = Pointer to NDIS packet to send
  *   Offset      = Offset in packet where packet data starts
  *   LinkAddress = Pointer to link address
- *   Type        = LAN protocol type (unused)
+ *   Type        = LAN protocol type
  */
 {
     PCHAR PacketBuffer;
@@ -49,6 +49,13 @@ VOID LoopTransmit(
     ASSERT_KM_POINTER(PC(NdisPacket));
     ASSERT_KM_POINTER(PC(NdisPacket)->DLComplete);
 
+    if (Type != LAN_PROTO_IPv4)
+    {
+        TI_DbgPrint(MAX_TRACE, ("Received unsupported protocol %u\n", Type));
+        PC(NdisPacket)->DLComplete(PC(NdisPacket)->Context, NdisPacket, NDIS_STATUS_NOT_SUPPORTED);
+        return;
+    }
+
     TI_DbgPrint(MAX_TRACE, ("Called (NdisPacket = %x)\n", NdisPacket));
 
     GetDataPtr( NdisPacket, 0, &PacketBuffer, &PacketLength );
@@ -112,7 +119,7 @@ NDIS_STATUS LoopRegisterAdapter(
 
   Loopback = IPCreateInterface(&BindInfo);
   if (!Loopback) return NDIS_STATUS_RESOURCES;
-    
+
   Loopback->MTU = 16384;
 
   Loopback->Name.Buffer = L"Loopback";
@@ -124,7 +131,7 @@ NDIS_STATUS LoopRegisterAdapter(
   AddrInitIPv4(&Loopback->Broadcast, LOOPBACK_BCASTADDR_IPv4);
 
   IPRegisterInterface(Loopback);
-    
+
   IPAddInterfaceRoute(Loopback);
 
   TI_DbgPrint(MAX_TRACE, ("Leaving.\n"));