here is a perl script I wrote to check hundred/thousand of ip's, is not perfect but it does what I want
#!/usr/bin/perl
use Net::DNS;
use IPC::System::Simple qw(capture);
use Mail::Sendmail;
use POSIX qw(strftime);
my $IPclass1 = "xx.xx.xx."; my $IPclass4 = "xx.xx.xx.";
my $date = strftime...