Two things - Perl does use the _r variants if available, but these provide thread-safety rather than async capabilities. Second, Net::DNS does provide a non-blocking variant. From its man page: 
=head2 Perform a background query and do some other work while waiting
for the answer.

  use Net::DNS;
  my $res    = Net::DNS::Resolver->new;
  my $socket = $res->bgsend("host.example.com");

  until ($res->bgisready($socket)) {
      # do some work here while waiting for the answer
      # ...and some more here
  }

  my $packet = $res->bgread($socket);
  $packet->print;

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In reply to Re: DNS lookups & signals by dave_the_m
in thread DNS lookups & signals by jfroebe

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