diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index b5e85a4d..b6a4e4af 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -1146,7 +1146,6 @@ tcp_receive(struct tcp_pcb *pcb)
 {
   s16_t m;
   u32_t right_wnd_edge;
-  int found_dupack = 0;
 
   LWIP_ASSERT("tcp_receive: invalid pcb", pcb != NULL);
   LWIP_ASSERT("tcp_receive: wrong state", pcb->state >= ESTABLISHED);
@@ -1208,7 +1207,6 @@ tcp_receive(struct tcp_pcb *pcb)
           if (pcb->rtime >= 0) {
             /* Clause 5 */
             if (pcb->lastack == ackno) {
-              found_dupack = 1;
               if ((u8_t)(pcb->dupacks + 1) > pcb->dupacks) {
                 ++pcb->dupacks;
               }
@@ -1224,11 +1222,6 @@ tcp_receive(struct tcp_pcb *pcb)
           }
         }
       }
-      /* If Clause (1) or more is true, but not a duplicate ack, reset
-       * count of consecutive duplicate acks */
-      if (!found_dupack) {
-        pcb->dupacks = 0;
-      }
     } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack + 1, pcb->snd_nxt)) {
       /* We come here when the ACK acknowledges new data. */
       tcpwnd_size_t acked;