use strict;
use Net::LDAP;

my $ld = Net::LDAP->new('myserver');
$ld->bind(dn=>'username',password=>'passwd');

my $result = $ld->search(base=>'cn=mydir',
                         scope=>'sub',
                         filter=>'(objectclass=*)');

while (my $entry = $result->entry())
{
  #do comparison here
}