use Net::Pcap;
my $dev  = Net::Pcap::lookupdev( \$err );
if ( defined $err ) {
    die "Unable to determine network device for monitoring - ", $err;
}
@devs = Net::Pcap::findalldevs(\$err);

 foreach (@devs) 
   {
   	  $dev= $_ ;
 	  print "$_ \n";
	  my ( $addr, $net, $mask );
     if ( Net::Pcap::lookupnet( $dev, \$net, \$mask, \$err ) ) 
         {die "Unable to look up device information for ", $dev, " - ", $err; }
     print "Device : $dev, Network Address : $net, NetMask : $mask \n";
   }