sub vm_tcp_dump {
        my $macaddress = $_[0];
        my $dns_name = $_[1];
        my $good_dns_name = undef;;
        eval{
                local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
                alarm 15;
                my $ping_thread = threads->new(\&vm_ping, $dns_name);
                print ("CMD: tcpdump -q -i eth0 'ether dst host $macaddress and proto ICMP and src host $hostname' -c 1\n");
                my $dumpdata =  undef;
                my $dump_thread = threads->new(sub {my $ipaddress = undef;
                                        $dumpdata = `tcpdump -q -i eth0 'ether dst host $macaddress and proto ICMP and src host $hostname' -c 1`;
                                        return $dumpdata;
                                        });
                $dumpdata = $dump_thread->join();
                print "\nTEST\n\n";
                print "\n".$dumpdata."\n\n";
                $good_dns_name = $ping_thread->join();
                alarm 0;
        };
        print "tcpdump done\n";
        return $good_dns_name;
}

sub vm_ping {
        my $dns_name = $_[0];
        my $good_dns_name;
        print("DNS: $dns_name\n");
        eval{
                local $SIG{ALRM} = sub {die "alarm\n" };
                alarm 15;
                my $data = `ping $dns_name -c 10 -s 256`;
                if(!($data =~ m/Destination Host Unreachable/g)){
                        $data =~ m/PING (.*).et.byu.edu/g;
                        $good_dns_name = $1;
                        print($data."\n");
                }
                alarm 0;
        };
        print "\nDONE\n\n";
        return $good_dns_name;
}