#!perl use Net::IP; use strict; print "+----------------------------------------------+ | addrs bits pref class mask | +----------------------------------------------+ "; my ($ip,$size,$class,$bits,$len); my $ip = new Net::IP('0'); for my $len (reverse (0..32)) { $ip->set("0.0.0.0/$len"); $size = $ip->size(); if ($size >=1048576) # 1024*1024 { $size /= 1048576; $size .= 'M'; } elsif ($size >= 1024) { $size /= 1024; $size .= 'K'; }; $len = $ip->prefixlen(); $bits = 32 - $len; if ($bits >= 24) { $class = 2**($bits-24); $class.= 'A'; } elsif ($bits >= 16) { $class = 2**($bits-16); $class.= 'B'; } elsif ($bits >= 8) { $class = 2**($bits-8); $class.= 'C'; } printf ("| %5s %6s %6s %7s %-15s |\n", $size,$bits,'/'.$len,$class,$ip->mask()); }; print "+----------------------------------------------+\n";