What is Floating IPs?
Learn what Floating IPs offers, how public IPv4 addresses are allocated, associated, and moved between instances, and how they're billed.
A Floating IP is a public IPv4 address that you allocate to your project from an external network and associate with an instance. The internet then reaches the instance at that address. The address stays in your project until you release it, so you can move it from one instance to another and keep it while you replace servers.
Key features
- Allocate on demand. Allocate an address, and optionally associate it with an instance in the same step. See Allocate a Floating IP.
- Choose the interface. For an instance with several network interfaces, choose the interface that the address maps to. See Associate a Floating IP with an instance.
- Move between instances. Keep the same public address when you replace the server behind it. See Move a Floating IP to another instance.
- Addresses for ports. Allocate an address straight onto a port of a network. See Allocate a Floating IP for a port.
- From the creation wizard. Give a new instance a public address when you create it. See Networking in the wizard.
- Filters. List all, associated, or unassociated addresses.
How it works
You allocate a Floating IP from a pool: an external network that your project is allowed to use for Floating IPs. The region's operator decides which external networks those are. You can't choose the address itself.
Associating a Floating IP maps the public address to the fixed IP address of one network interface. The interface's subnet must be attached to a router whose external gateway is on the Floating IP's pool. An interface holds at most one Floating IP. An associated address is Active, and an unassociated one is Down.
Allocating, associating, disassociating, and releasing run as asynchronous operations. A new address shows allocating… in the list until the cloud has assigned it.
Floating IPs is available where the project's region offers it. In a region that doesn't, the console leaves Floating IPs out of the menu, a link to a Floating IP page shows a notice instead of the page, and new Floating IPs are refused.
Use cases
- Public servers. Reach a web server or an SSH jump host from the internet.
- A stable public address. Keep the address that your DNS records and your partners' allowlists use, and move it to a new instance when you replace a server.
- Temporary access. Associate an address for a maintenance window, and disassociate it afterward.
Billing
| Dimension | How it's billed |
|---|---|
| Floating IP | Per hour while the address is allocated, whether or not it's associated. |
Every Floating IP is billed for at least 60 seconds over its lifetime. Release the addresses that you no longer need to stop their billing. Traffic that leaves the cloud through a router's external gateway is billed as internet egress, when egress has a price in your region. See Billing in Virtual Networks.
When you delete an instance, the Floating IP that the creation wizard allocated for it is released, and a Floating IP that you allocated separately stays allocated and billed. See Stop all charges for an instance. For how usage becomes charges on your invoice, see How billing works. For prices, see Pricing.
Limits
- Floating IPs are IPv4 addresses.
- An interface holds at most one Floating IP.
- In the console, you associate Floating IPs with instances. You can also allocate a Floating IP for a port on a network's Ports / devices tab.
- A port on an external network can't take a Floating IP, because its address is already public.
- Floating IPs count against the subscription's quota and the project's allocation. A new project starts with an allocation of up to 2 Floating IPs, as far as the subscription's limits have room left. See Quotas.
Related services
- Virtual Networks: the routers and external gateways that Floating IPs need.
- Security Groups: the ingress rules that decide what reaches the address.
- Virtual Machines: the instances that you associate addresses with.