Usually a dedicated IP address is a technical requirement for the SSL installation. For proper SSL functionality it is recommended to have a separate dedicated IP for each certificate.
However, nowadays it is possible to install multiple SSL certificates using a shared IP address thanks to the SNI (Server Name Indication) technology.
A mandatory use of a dedicated IP is determined by the type of the hosting server. If your website is hosted by a web-hosting company, you need to contact them to clarify whether it is necessary for you to purchase a dedicated IP address or they are able to provide you with SNI.
If the server is self-managed, you may refer to the server documentation to find out whether SNI technology is available on your machine.
Basically, the main advantage of the SNI technology is a possibility of installing multiple certificates and supporting multiple servers on the same IP address, which helps improve security and trust by using unique certificates for different sites, identities and brands.
Even though having the opportunity to use multiple SSL certificates on a single IP address seems to be more beneficial, SNI technology has a number of incompatibility issues with older browsers and operating systems.
SNI is not compatible with:
- Windows XP + any version of Internet Explorer (6, 7, 8, 9)
- Internet Explorer 6 or earlier
- Safari on Windows XP
- BlackBerry Browser
- Windows Mobile up to 6.5
- Nokia Browser for Symbian at least on Series60
- Opera Mobile for Symbian at least on Series60
Thus, a dedicated IP address is a better option in terms of reliability, browser compatibility and lower risks of server downtime. Here are five main reasons a dedicated IP address is worth paying for:
- Overall stability. Having a dedicated IP address eliminates the risk of brief downtime on the server while refreshing the IP address.
- Email server stability. Preventing the server IP from getting banned or blacklisted for spam, which may be caused by other users when using a shared IP address.
- Remote access. With special programs for remote access it is possible to access the server no matter where you are in the world.
- Running an FTP server. Using FTP to share files with clients, partners, friends and family or enhancing your organization. FTP is a very reliable and efficient way to transfer data from one computer to another.
- Anonymous FTP. Providing access via FTP software to a special directory of your website. For this feature to function properly, it is usually required to have a dedicated IP address.
To sum up, ordering a dedicated IP address is not mandatory if SNI technology is available to use and the issue of SNI incompatibility is not critical for you. If you wish to achieve the highest level of compatibility, it is recommended to purchase a dedicated IP from your service provider.
Ordering a dedicated IP is mandatory in case the hosting server does not support SNI technology or if it is a requirement established by your hosting company.