A static IP, means that your site will be assigned a unique and unchanging IP address. You can purchase a static IP  from the following URL:

http://www.fastwebhost.com/addon.html

To get static IP you need provide the below mentioned Justification details.

Our allocation of IP addresses is limited by ARIN's new policies.

1.Web Hosting with SSL

2.Custom Name Server Addresses

3.Applications Requiring a Unique Port

4.Virtual Machine Hosting

5.Network Equipment and IPs used for Addressing (Routers etc)