How to check if a network port is open on linux?

Question

How can I know if a certain port is open/closed on linux ubuntu, not a remote system, using python? How can I list these open ports in python?

• Netstat: Is th

Answer 1

For me the examples above would hang if the port wasn't open. Line 4 shows use of settimeout to prevent hanging

import socket

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(2)                                      #2 Second Timeout
result = sock.connect_ex(('127.0.0.1',80))
if result == 0:
  print 'port OPEN'
else:
  print 'port CLOSED, connect_ex returned: '+str(result)