When using the term dedicated IP, we are referencing the difference between a shared IP and a dedicated IP address.
Shared IP Address
A shared IP is used by several other servers alongside each other. This means that users have potential of bumping into other servers on the same IP and attacks directed at another service on the IP may too affect your service. This also often means you have a non-standard port for your game server and is generally confusing for many users when trying to setup DNS. For these reasons, we do not support shared IP addresses for game servers.
Dedicated IP Address
A dedicated IP is assigned to one customer for one service. This keeps our customers isolated from one another and ensures the standard port for game servers are used. This allows for much easier DNS configuration for customers, as well as isolates them to a single IP address, should they want to use any additional ports. We assign this at no additional charge to our customers.