require 'socket'
mtu = 1500   # standard ethernet
  
s_sock = TCPServer.new('0.0.0.0',12345)
s_conn = s_sock.accept
response  = "x" * (mtu - 40 - 12 - 10)  # IP/TCP hdr, timestamp, gap
response << "123456789\r"               # fill the gap
s_conn << response
sleep 1
s_conn << "\nxxxxxxxxxDONE\r\n"
s_conn.close