diff --git a/NetworkPkg/TcpDxe/TcpInput.c b/NetworkPkg/TcpDxe/TcpInput.c
index 04c8a8269e..f8845dca47 100644
--- a/NetworkPkg/TcpDxe/TcpInput.c
+++ b/NetworkPkg/TcpDxe/TcpInput.c
@@ -1,7 +1,7 @@
 /** @file
   TCP input process routines.
 
-  Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>
 
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
@@ -738,6 +738,7 @@ TcpInput (
   TCP_SEQNO   Right;
   TCP_SEQNO   Urg;
   UINT16      Checksum;
+  INT32       Usable;
 
   ASSERT ((Version == IP_VERSION_4) || (Version == IP_VERSION_6));
 
@@ -1306,9 +1307,27 @@ TcpInput (
       }
 
       if (TCP_SEQ_LT (Right, Tcb->SndNxt)) {
-
-        Tcb->SndNxt = Right;
-
+        //
+        // Check for Window Retraction in RFC7923 section 2.4.
+        // The lower n bits of the peer's actual receive window is wiped out if TCP
+        // window scale is enabled, it will look like the peer is shrinking the window.
+        // Check whether the SndNxt is out of the advertised receive window by more than
+        // 2^Rcv.Wind.Shift before moving the SndNxt to the left.
+        //
+        DEBUG (
+          (EFI_D_WARN,
+          "TcpInput: peer advise negative useable window for connected TCB %p\n",
+          Tcb)
+          );
+        Usable = TCP_SUB_SEQ (Tcb->SndNxt, Right);
+        if ((Usable >> Tcb->SndWndScale) > 0) {
+          DEBUG (
+            (EFI_D_WARN,
+            "TcpInput: SndNxt is out of window by more than window scale for TCB %p\n",
+            Tcb)
+            );
+          Tcb->SndNxt = Right;
+        }
         if (Right == Tcb->SndUna) {
 
           TcpClearTimer (Tcb, TCP_TIMER_REXMIT);