if ( $select -> can_read( 0 ) ) {
    my $remote = recv ( $pinger, $buff, SIZE, RCV_FLAGS );
    if ( $debug ) { 
         print "result from ", unpack("C*",$remote), ":",
         unpack ( "C*", $target_addr), "\n"; 
    }

    # sometimes ICMP replies come from other devices, filter those out
    if ( $remote eq $target_addr ) {
        $received++;
    }
}