diff --git a/src/aodv/test/tcp-chain-test-9-0.pcap b/src/aodv/test/tcp-chain-test-9-0.pcap
index f2a57ed28..12038ecd7 100644
Binary files a/src/aodv/test/tcp-chain-test-9-0.pcap and b/src/aodv/test/tcp-chain-test-9-0.pcap differ
diff --git a/src/internet/model/tcp-socket-base.cc b/src/internet/model/tcp-socket-base.cc
index fa4ae37b8..3de68ae13 100644
--- a/src/internet/model/tcp-socket-base.cc
+++ b/src/internet/model/tcp-socket-base.cc
@@ -683,6 +683,11 @@ TcpSocketBase::DoForwardUp (Ptr<Packet> packet, Ipv4Header header, uint16_t port
                     ":" << tcpHeader.GetSequenceNumber () + packet->GetSize() <<
                     ") out of range [" << m_rxBuffer.NextRxSequence () << ":" <<
                     m_rxBuffer.MaxRxSequence () << ")");
+      // Acknowledgement should be sent for all unacceptable packets (RFC793, p.69)
+      if (m_state == ESTABLISHED && !(tcpHeader.GetFlags () & TcpHeader::RST))
+        {
+          SendEmptyPacket (TcpHeader::ACK);
+        }
       return;
     }