An IP address is a unique number that identifies a website or a web server on the Internet, so in the event that you have a dedicated IP, it will be employed solely by your sites and will not be shared with other people as it happens with shared website hosting accounts. In case you have your own server, you will have a dedicated IP, but you may require extra ones for a variety of purposes. In case you have an electronic store, for instance, you shall need an SSL certificate for it, so as to ensure that the payment information your clients submit will be encrypted and safe. The same is valid if you have a login form of some type and you wish the usernames and the passwords that visitors input to be secured. The SSL certificate requires a dedicated IP, which needs to be different from the one which you already have on the machine. You may also need a separate IP for an application such as a VoIP server, or if you would like a slightly better overall performance for a particular website, which will affect its position in search engine results.