How can I monitor when my router's IP address changes?

Our ISP uses DHCP, so from time to time our router's external IP address will change.



I can login to the router's admin panel to see what it's current IP address is. And I suppose I could write something to scrape that page periodically to check for a new value.



But this seems like a common issue and thought someone could point me to an existing solution.



* The best would be a tool that runs on a Mac OS-X that could monitor the router's external IP address WITHOUT scraping the page and email me the new address.

* A close second is a way to know the router's IP without without the screen scrape (I'm not sure it's possible, but I'm not a networking expert).



ThanksHow can I monitor when my router's IP address changes?
Most residential routers support a tool called Dynamic DNS that will update a name lick MYNAME.dyndns.org with the IP address every time that it changes. This works well for me because I can then always reference MYNAME.dyndns.org instead of keeping up with IP address changes. Additionally, even if your router doesn't support it internally, you can run their client on your computer and it will keep up with what your external, PUBLIC IP Address is through the same method.How can I monitor when my router's IP address changes?
Since you know your router's internal IP and your ISP's IP, the first thing that comes to my mind is to use traceroute command (or its equivalent on Mac OS), grab the appropriate line (that contains your router's external IP), and extract the IP address.
you move from place to place so there will be a change in IP address i think its a laptop so try asking your shopkeeper