One way that is useful--especially if you have a local network connected to the net via a NAT box and your external IP is different to your local ip--is to parse it out of a request made to one of the zillions of "What is my IP" pages spread around the net. The address shown below is just the first one google turned up when I searched.

(It would probably not be freindly of us if we all hit this one site. If you want to try this, feed the quoted string above into google, next page 2 or 3 times and then pick one. You might need to tweak the regex a bit.) 

#! perl -sw
use strict;
use LWP::UserAgent;

my $ua = LWP::UserAgent->new;
my $request = HTTP::Request->new('GET', 'http://www.internet-help.net/
+cgi-bin/ip-address.pl');
my $response = $ua->request($request);
print $response->{_content} =~ m/(\d+\.\d+\.\d+\.\d+)/;

[download]
Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

In reply to Re: Detecting when my ISP changes my IP by BrowserUk
in thread Detecting when my ISP changes my IP by meonkeys

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.