Concepts

STACKIT Public IP Address gives you the opportunity that your resources can be reached from the public internet. It is an independent entity that you can attach or detach from your resources as needed. Speaking of known concepts a Public IP Address is an actual implementation of a floating address.

Your resources don’t need a STACKIT Public IP Address attached to reach the internet. Every Virtual Network has a router that acts as a gateway with a publicly routed IPv4 address bound to it. Read Basic concepts of Virtual Network to get a better understanding.

Use cases

• You want to reach a resource inside STACKIT’s public cloud from the internet.
• You want to access a destination in the internet with an IP address, that is exclusively used by this resource.

Implementation

Technically STACKIT Public IP Address is realised via network address translation (1:1 NAT) between the internet and the VM with the bound Public IP Address. On the VM itself there is no Public IP Address configured (e.g. as an interface). Instead the local IP address of the VM will be exchanged with the Public IP Address when accessing the internet and vice versa. In this case the public IP will be replaced with the local IP address of the resource. There is a 1:1 relation between a Public IP Address and a bound resource. IPv6 is realised with NAT64, defined in RFC 6146.

Due to the implementation of the Public IP Address as a NAT-solution, the address translation happens on the network layer, before the data packets reach the VM. Therefore the Public IP Address is not visible on the VM itself (e.g. as an interface). Keep this in mind, when you manually configure your services.

IPv6 (GA is planned for H1/2026)

STACKIT Public IP Address enables you to have your resources reachable by IPv6. STACKIT is using stateful NAT64 (RFC 6146) to achieve this task. The gateway maintains a session table to map incoming IPv6 connections to your IPv4 address and manage the return traffic.

The NAT64 gateway acts as a stateful translator between the protocols. It accepts requests from IPv6 clients, converts them into IPv4 packets, and establishes a tracked session to your STACKIT public IPv4 address.

Read Setup IPv6 reachability to learn, how you can setup IPv6 reachability for your resources.