A DigitalOcean Reserved IP address is a publicly-accessible static IP address that you can assign to a Droplet and then reassign to another Droplet later, as needed. You can implement a failover mechanism with reserved IPs to build a high availability infrastructure.
By default, you can reserve three reserved IPs per account. If you reach this limit, you can request more through the control panel.
Reserved IPs cannot be assigned to more than one Droplet at a time.
Droplets cannot have more than one Reserved IP address assigned to them at a time.
Reserved IPs do not support PTR (rDNS) records.
We do not support IPv6 reserved IPs. All reserved IPs are IPv4.
We do not support reserved IPs for DigitalOcean Kubernetes worker nodes.
A Droplet must have an anchor IP before you can assign a reserved IP to it. Droplets created after 20 October 2015 automatically have an anchor IP, and you can create an anchor IP on older Droplets.
Droplets created from a custom image do not receive an anchor IP address and do not require one to use a reserved IP. When you assign a reserved IP address to a Droplet created from a custom image, the reserved IP is automatically mapped to the Droplet’s public IPv4 address instead of an anchor IP.
Reserved IPs do not support SMTP traffic.