Category: Web stuff
Author/Contact Info Ryan Whitworth lithron@gmail.com
Description: A "smart" client that will update your Dyndns.org (or other domain from the company) to your current IP address. Works from behind a NAT (via www.whatismyip.com). Only tested under Win32 with Cygnus' Cygwin tools installed. Requires LWP::Simple and Socket.
Updated : removed the call to nslookup thanks to code provided by TheFluffyOne 
#!/usr/bin/perl -w
use strict;
use warnings;
use LWP::Simple;
use Socket;

my $login = 'test';
my $password = 'test';
my $domain = 'test.mine.nu';
my $mx = 'mail.test.mine.nu';

my $ipaddress = LWP::Simple::get("http://www.whatismyip.com");
if ($ipaddress =~ /([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})/) 
{ 
  $ipaddress = $1; 
}

my $nslookup = "0.0.0.0";
if ($nslookup = gethostbyname($mx)) {
  $nslookup = inet_ntoa($nslookup);
} else {
  print "Could not resolve domain name, check $domain is correct\n";
  print "Going to try to update information for $domain anyway ...\n";
}

if ($ipaddress eq $nslookup) {
  print "Nothing to update.  Current IP ($nslookup)";
  print " = DNS address ($ipaddress)\n";
  exit(0);
}

print "Updating the IP address ($ipaddress) now ... \n";

my $response = LWP::Simple::get("http://$login:$password\@" .
"members.dyndns.org/nic/update?system=dyndns&hostname=$domain" .
"&myip=$ipaddress&wildcard=ON&mx=$mx&backmx=NO&offline=NO");

print "Status : $response\n";
Replies are listed 'Best First'.
Re: Dyndns.org Updating Client
by allolex (Curate) on Nov 24, 2003 at 00:58 UTC
[reply]
      I like updatedd for its very simple interface, myself.

      Makeshifts last the longest.

[reply]
Re: Dyndns.org Updating Client
by b10m (Vicar) on Nov 23, 2003 at 23:27 UTC
    If anyone cares to tell me how to change my call to nslookup to something more perl-ish (or more portable), I'd be glad to change it.

    Net::DNS is your friend in this matter :)

    --
    B10m
[reply]
      Net::DNS doesn't seem to like my Cygwin Perl 5.8.1 install at home, nor my Cygwin 5.8.0 install at work :-( When I get a chance I'll file bug reports to the author.

      Update:Perl 5.8.2 just got released for Cygwin, and Net::DNS works fine.. although I still prefer the solution given below. It doesn't require more modules, and I like that :-)
[reply]
        I didn't know this. The CPAN test page doesn't show passed, nor failed tests for cygwin of new(er) versions :(

        What about Net::Nslookup ?

        Update: sorry, but I don't have a Win32 system that I could use to test this on myself

        --
        B10m
[reply]
Re: Dyndns.org Updating Client
by TheFluffyOne (Beadle) on Nov 24, 2003 at 19:42 UTC

    I tend to use:

    use Socket;
if ($ip = gethostbyname($domain)) {
    $ip = inet_ntoa($ip);
    print "IP address is $ip\n";
} else {
    print "Could not resolve name.\n";
}

    [download]

    Not amazing, but does the job :) I assume you're going out to "whatismyip.com" because the IP address you want is not the box you run the script on?

    Gordon.

[reply]
[d/l]
      I like the code, and the concept. I'll change things when I get home and do an update. I use whatismyip.com because the computer I run the code on is behind a NAT. Then I let the NAT forward ports to my internal computers. Plus, for those that don't have a NAT, it always retrieves the correct world routeable IP address, instead of grabbing the first network card's IP. I believe the above code could easily replace my call to nslookup. Thank you so much :-)
[reply]

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