Port knock with python - no expire

import sys,time,struct,hmac
from socket import gethostbyname, inet_aton, socket, AF_INET, SOCK_DGRAM
from Crypto.Hash import SHA256

m = hmac.new(sys.argv[1], digestmod=SHA256)
m.update(inet_aton(gethostbyname(sys.argv[2])))
m.update(struct.pack("i", (int)(time.time() / 60)))

s = socket(AF_INET, SOCK_DGRAM)
s.connect((sys.argv[3], (int)(sys.argv[4])))
s.send(m.hexdigest())
s.close()