I've not used it myself yet, but CPAN module Sys::HostIP appears to be what you're looking for.   From the module source:

NAME
Sys::HostIP - Try really hard to get IP addr.

SYNOPSIS
use Sys::HostIP;
$ipaddr= hostip; # get (text) dotted-decimal ip 

use IO::Socket;
use Sys::Hostname;
# Have to try non-cannonical name first, since there
# is a better chance the computer knows itself than
# of DNS knowing it.
if($^O eq 'MSWin32')
    # check ipconfig.exe 
    #     (Which does all the work of checking the registry,
    #     probably more efficiently than I could.)
    # check nbtstat.exe 
    #     (Which does all the work of checking WINS,
    #     more easily than Win32::AdminMisc::GetHostAddress().)
    # check /etc/hosts entries 
    # check /etc/lmhosts entries 
    #     (It will only be here if the file has been modified since th
+e
    #     last WINS refresh, which is unlikely, but might as well try.
+)
elsif($^O=~ /IX|ux/i)
    # check /etc/hosts entries 
# last resort: ping (which can be very slow)
[download]

Ya just gotta love cpan.
    cheers,
    Don
    striving for Perl Adept
    (it's pronounced "why-bick")