use Net::Ping;

           $p = Net::Ping->new();
           print "$host is alive.\n" if $p->ping($host);
           $p->close();

           $p = Net::Ping->new("icmp");
           foreach $host (@host_array)
           {
               print "$host is ";
               print "NOT " unless $p->ping($host, 2);
               print "reachable.\n";
               sleep(1);
           }
           $p->close();

           $p = Net::Ping->new("tcp", 2);
           while ($stop_time > time())
           {
               print "$host not reachable ", scalar(localtime()), "\n"
                   unless $p->ping($host);
               sleep(300);
           }
           undef($p);

           # For backward compatibility
           print "$host is alive.\n" if pingecho($host);