title: Is SYN + FIN segment blocked by Linux stack?
body: <p>I'm trying to send a TCP segment with SYN+FIN control bits set on a Linux machine (kernel 3.16) to another one for testing purposes with scapy:</p>
  
  <pre><code>from scapy.all import *
  
  sport = random.randrange(1024, 65535)
  dport = 45000
  
  pkt = IP(dst=X.X.X.X)/TCP(sport=sport, dport=dport, flags="SF")
  send(pkt)
  </code></pre>
  
  <p>The segment can be seen with wireshark on sender, however, it does not seem to be sent to X.X.X.X as wireshark on that machine do not see the segment at all. Is Linux kernel blocking the sending of SYN+FIN segments (as this kind of control bits combination in a segment should never occur)? Else, what could be the reason for such behaviour? How can I achieve sending SYN+FIN segments?</p>