Of course, your Win32 box may have multiple network cards and IP addresses, so most/all of these answers are only partial solutions.

I would like to recommend the Win32::IPHelper module:

use strict;
use Win32::IPHelper;

my @Adapters;
Win32::IPHelper::GetAdaptersInfo(\@Adapters);

foreach my $Adapter (@Adapters) {
    foreach my $IP (@{$Adapter->{IpAddressList}}) {
        print "IP = $IP->{IpAddress}\n";
    }
}
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