An IP address is a unique number which identifies an Internet site or a server on the world-wide web, so if you have a dedicated IP, it shall be used solely by your Internet sites and shall not be shared with other individuals as it happens with shared Internet hosting accounts. In case you have your own hosting server, you will have a dedicated IP, but you may need extra ones for various purposes. In case you have an online store, for example, you shall need an SSL certificate for it, to make certain that the payment info which your clients submit will be encrypted and safe. The same is valid in case you have a login form of some type and you want the usernames and the passwords that visitors type in to be secured. The SSL certificate requires a dedicated IP, which ought to be different from the one that you already have on the server. You could also need a separate IP for an application such as a VoIP server, or if you would like a slightly better efficiency for a given site, which will influence its position in search engine results.