use Mail::CheckUser qw/ check_email last_check  /;
BEGIN{
    $Mail::CheckUser::Skip_SMTP_Checks = 1;
    $Mail::CheckUser::Treat_Timeout_As_Fail = 1;
    $Mail::CheckUser::Debug = 1;
}
##</code><code>##

use Net::DNS::Resolver ;
use Data::Dump;
my $f = Net::DNS::Resolver->new; 
dd( $f->query( q{abczz123ffz.com}, 'MX') );
dd($f);
dd($f->query(q{b.com}, 'MX') );
dd($f);
__END__
undef
bless({
  adflag         => 0,
  answerfrom     => "192.168.1.254",
  cdflag         => 0,
  debug          => 0,
  defnames       => 1,
  dnsrch         => 1,
  dnssec         => 0,
  domain         => "attlocal.net",
  errorstring    => "NXDOMAIN",
  force_v4       => 0,
  force_v6       => 0,
  ignqrid        => 0,
  igntc          => 0,
  nameserver4    => ["192.168.1.254"],
  nameserver6    => [],
  persistent_tcp => 0,
  persistent_udp => 0,
  port           => 53,
  prefer_v6      => 0,
  recurse        => 1,
  retrans        => 5,
  retry          => 4,
  searchlist     => ["attlocal.net"],
  srcaddr        => "0.0.0.0",
  srcport        => 0,
  stayopen       => 0,
  tcp_timeout    => 120,
  tsig_rr        => undef,
  udp_timeout    => undef,
  udppacketsize  => 0,
  usevc          => 0,
}, "Net::DNS::Resolver")
undef
bless({
  adflag         => 0,
  answerfrom     => "192.168.1.254",
  cdflag         => 0,
  debug          => 0,
  defnames       => 1,
  dnsrch         => 1,
  dnssec         => 0,
  domain         => "attlocal.net",
  errorstring    => "NXDOMAIN",
  force_v4       => 0,
  force_v6       => 0,
  ignqrid        => 0,
  igntc          => 0,
  nameserver4    => ["192.168.1.254"],
  nameserver6    => [],
  persistent_tcp => 0,
  persistent_udp => 0,
  port           => 53,
  prefer_v6      => 0,
  recurse        => 1,
  retrans        => 5,
  retry          => 4,
  searchlist     => ["attlocal.net"],
  srcaddr        => "0.0.0.0",
  srcport        => 0,
  stayopen       => 0,
  tcp_timeout    => 120,
  tsig_rr        => undef,
  udp_timeout    => undef,
  udppacketsize  => 0,
  usevc          => 0,
}, "Net::DNS::Resolver")