> For the complete documentation index, see [llms.txt](https://docs.ionos.com/cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ionos.com/cloud/network-services/vdc-networking/ip-failover/overview.md).

# Overview

IONOS CLOUD IP Failover: overview of NIC-level IP failover for high availability

IP Failover enables automatic reassignment of public [<mark style="color:blue;">IP addresses</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#internet-protocol-ip-address) to standby virtual machines in the event of a failure, ensuring high availability and business continuity for your applications.

## Key concepts

An IP failover group consists of the following components:

### Members

* A shared (reserved, public) [<mark style="color:blue;">IP address</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#internet-protocol-ip-address) that is assigned to all member NICs of the failover group.
* Enables communication to continue during a failure event.
* Multiple IP failover groups can be configured for different services.
* A server can be a member of multiple IP failover groups.
* Servers should ideally be distributed across different [<mark style="color:blue;">Availability Zones</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#availability-zone) for redundancy
* Users must have access rights for the IP addresses they wish to use.
* Failover rules are managed at the operating system level using high-availability or fail-over configuration features.

### Master

* Represents the primary node in the IP failover group during initial provisioning.
* Corresponds to the master of the HA setup on your virtual machines.
* Can be changed without needing to update the failover group configuration in the DCD.

### Primary IP Address

* Can be configured as either the primary or additional IP address for the failover group.
* **Recommended:** Use the failover IP as the primary IP address, as it is used to calculate the gateway IP (beneficial for backup solutions).
* **Note:** This will replace any previously provisioned primary IP address.
* **Limitation:** When multiple IP failover groups exist on a LAN, a [<mark style="color:blue;">NIC</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#network-interface-card-nic) can only be used once for a primary IP address across all groups (the DCD will alert you accordingly).


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