External firewall (€196 / month) Add this option if you want to have an external firewall on your server. Then a technician will put up the firewall rules you request. 

  Antispam (€4.5 / month) We will add your email server to our spam-​​front where the mail is analyzed and spam is removed before it gets to your inbox. 

   Reverse DNS (one-time fee €27) Add this option if you want reverse DNS. Then a technician will add this for you after communicating with you about it.