Not quite. My method was far from what this guy is doing. I only did a minimal ping, one packet per IP with a Python script:

  s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.getprotobyname("icmp"))
  for address in addresses:
    s.sendto(pkt, (address, 1))
  s.close()

At the same time, I had tcpdump running, i.e. "tcpdump -i en1 icmp[icmptype] == icmp-echoreply" to capture the replies.