SSL Certificates, and why you need a Dedicated IP.

A SSL Certificate is recommended for all sites that accept credit card payments or customer information that needs to remain secure. SSL encrypts your information before sending and also activates the secure lock in your web browser.

If you purchase a SSL Certificate then a Dedicated IP is also required. This will mean that your site has its own unique IP number.

Why do I need a dedicated IP for the SSL installation?

Because of the process that the web server uses to make the SSL connection:

For shared hosting (when many domains are on one IP) the web browser sends the name of the domain being requested inside the http headers along with the request. This way, the name of the domain you are trying to access is known, even though there are many domains on that specific IP address.

When SSL is involved, first the certificate connection is made.  The certificate request received by the server only contains the IP address, not the domain name.  The certificate must be sent before other information is exchanged.  So only one certificate per IP, as otherwise, the server would have no way of knowing which certificate to send.