#!/bin/perl
use Net::IP::AddrRanges;
use Sys::HostAddr;
my @LocalSubnets;
push @LocalSubnets, "192.168.100.0/24";

    # lokale adresse ermitteln
    my $sysaddr = Sys::HostAddr->new();
    my $ip;
    my $noiperr=eval { $ip = $sysaddr->main_ip('route'); };
    # in einem netz in LocalSubnets?
    if ($noiperr) {
    my $ranges = Net::IP::AddrRanges->new();
    $ranges->add(@LocalSubnets);
    if (!$ranges->find($ip)) {
	print "in\n";
    }
    print "out\n";
    }
    else {
	print "no ip!\n";
    }