Detect IP changes

Nagy László Zsolt nagylzs at freemail.hu
Thu Mar 20 16:11:03 CET 2003


>Is there a reliable way to detect the change of a dynamic IP address ?
>If I use socket.gethostbyname('my_dynip_name') I still get the old IP, even
>thougt my system's DNS has been refreshed with the new name-address binding
>...
>A solution should be platform independent.
>
>Thanks for your answers!
>  
>
It seems you are having the same problems I was having.. :-)
You can use this module below. You must have an active internet connection
to load it. Call the getmyip() function to get your ip address. On 
multi-hosted machines,
it will return the IP address of your external (internet) connection.


   Laci 1.0


#!/usr/bin/env python
"""Get IP address towards external addresses"""

import socket
import thread
import threading
import time

UPDATE_INTERVAL = 5 # Update cached ip in every 60 minutes.
COMMON_HOST = 'www.google.com'
COMMON_PORT = 80

_lock = threading.Lock()
_cached_ip = None

def _getmyip():
    global _lock
    global _cached_ip
    s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    s.connect((COMMON_HOST,COMMON_PORT))
    ip = s.getsockname()[0]
    s.close()
    _lock.acquire()
    try:
        _cached_ip = ip
    finally:
        _lock.release()


def getmyip():
    global _lock
    global _cached_ip
    _lock.acquire()
    try:
        return _cached_ip
    finally:
        _lock.release()

def _update_cached_ip():
    while 1:
        time.sleep(UPDATE_INTERVAL)
        _getmyip()

_getmyip()
thread.start_new_thread(_update_cached_ip,())







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