[LINK] technical question: security alert

[Chris Maltby]

> On Wed 2009-03-04 22:48:24 UTC+1100, Ivan Trundle (ivan at itrundle.com) wrote:
>> This might sound na?ve, but surely Winders and other non-Mac Unix  
>> machines have simple software that can show your external IP address  
>> in realtime, all of the time? Without resorting to external websites?
 
On Wed, Mar 04, 2009 at 11:31:32PM +1100, andrew clarke wrote:
> ipconfig for Windows.
> 
> ifconfig for pretty much all other modern-day OSes (Linux, BSD, OS X).
> 
> Both are command-line utilities that are (usually!) supplied with the
> OS.  They will show your Internet IP address unless you're behind a
> router (eg. most ADSL routers) - in which case it will probably show
> your Intranet (LAN) address, instead of what you want.

In general there is no way to find out what IP address will be on your
packets after all Network Address Translation (NAT) has occurred by the
devices between your client and the Internet proper.

Asking a site like "whatismyip.com.au" may be all you can do unless you
have control of all the devices (including routers, satellite modems etc)
that may be doing NAT, and you can ask them what their current external
address might be. You could script either of these if necessary.

One thing you can be sure of, is if ipconfig/ifconfig shows an address
in the 10/8, 172.16/20 or 192.168/16 networks it's not your "real" IP.

Chris