title: New to scapy. Trying to understand the sr()
body: <p>I am new to scapy and I am trying to use the <code>sr</code> and <code>sr1</code> functions to understand their workings.</p>
  
  <p>I was trying to craft the following packet and I see that it has sent 1 packet but it says that it has received 581 packets. Can someone please help me understand why it's showing so many packets received.</p>
  
  <p>Received 1373 packets, got 0 answers, remaining 1 packets</p>
  
  <pre><code>&gt;&gt;&gt; p=sr(IP(dst="192.168.25.1")/TCP(dport=23))
  .Begin emission:
  .....Finished to send 1 packets.
  ...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^C
  Received 581 packets, got 0 answers, remaining 1 packets
  &gt;&gt;&gt; p
  (&lt;Results: TCP:0 UDP:0 ICMP:0 Other:0&gt;, &lt;Unanswered: TCP:1 UDP:0 ICMP:0 Other:0&gt;)
  </code></pre>
  
  <p>My TCPDump output does not show that it received so many packets.</p>