#!/usr/bin/perl -w

use strict;
use Net::DNS;

my $domain_file = $ARGV[0];
die "usage: $0 domainfile" unless( $domain_file and -e $domain_file );
my $resolver = new Net::DNS::Resolver;

open my $fh, '<', $domain_file or die $!;

while( my $domain = <$fh> ){
    chomp $domain;
    # MX-Record abfragen
    my @mxrecs = mx($resolver, $domain);
    if (@mxrecs){
        # Gefunden!
        foreach my $rec (@mxrecs){
            print $rec->preference, " ",
                  $rec->exchange, "\n";
        }
    }
    else{
        # Leere Liste, Fehler!
        print "Kein MX-Record für $domain: ",
                $resolver->errorstring, "\n";
    }
}