Networks Gen3

In a Nutshell

Each bwCloud-OS instance launched using the standard method is automatically assigned a public IP address. Instances are also assigned a persistent FQDN based on their name, project and region. Domain hosting is not provided, but you can point your own domain to the instance’s FQDN using a CNAME record.

Networks & IP-addresses

Will my instance receive a public IP?

IPv6-addresses: yes

IPv4-addresses: no

By default every VM will receive a private IPv4-addresses. Egress IPv4 connectivity is provided via SNAT.

📌 Note: IPv4 ingress connectivity is also possible in every region via request.

📌 Note: Each region in bwCloud-OS has its own set of IP address ranges.

How long does an IP remain assigned to my instance?

The IP address(es) assigned to your instance remains associated with it for the entire lifetime of the instance — even if you stop (shut down) the instance.

The IP is only released when the instance is deleted (terminated). After termination, the IP is returned to the regional pool and may be reassigned to another instance in the region.

📌 Note: Floating IPs will remain even after an Instance deletion. They have to be released manually.

Are Floating IPs also available for instances?

Yes.

Floating IPs provide a mechanism to 1:1 NAT a public IPv4 addresse to a private IPv4 address of an instance enabling ingress IPv4 connectivity.

For more information and detailed setup instructions, see the guide below.

➡️ Routers and Floating IPs Guide.

Domains and FQDNs

Does bwCloud-OS also assign FQDNs?

Yes. Every running instance in bwCloud-OS is automatically assigned a generic hostname (FQDN). This allows the instance to be reached via a persistent network identifier, even if its public IP address changes. This FQDN is valid for the lifetime of the instance.

Format of the instance's FQDN

• The UUID of the instance
• The project name
• The region abbreviation (e.g., ma for Mannheim)
• The domain suffix: .bw-cloud-instance.org

Example:

If your instance name is kos, the project is called yarn and it runs in Mannheim (ma), the FQDN will be:

kos.yarn.vm.ma.bwcloud-os-instance.de.

The FQDN can also be found in the Dashboard, on the Instances -> Network -> Interface page.

Can I get a request more DNS records in bwCloud-OS?

Yes.

We manage the top level domain bwcloud-os-instance.de. It is possible to request a DNS record for a floating IP for example.

Can I get a custom domain via bwCloud-OS?

No, bwCloud-OS does not provide custom domain hosting. However, you can use your own domain — either through your home institution or an external domain provider — to point to your instance.

Some options are described below.

How can I point a domain to an instance?

You can point a domain to your instance in two main ways:

🔹 CNAME to the instance FQDN

The instance’s FQDN is based on its UUID and region. Since the UUID is persistent for the instance's lifetime (even if the instance is stopped and started again), you can safely set a CNAME record like:

myvm.example.org → instance-name.project-name.vm.region.bwcloud-os-instance.de

🔹 Dynamic DNS

Alternatively, you can configure a Dynamic DNS setup where your VM updates its IP in a third-party DNS service — especially if you don’t have your own domain, or your use case involves frequently changing or multiple IPs.

Can I get a certificate from bwCloud-OS?

No, bwCloud-OS does not provide certificates. However, you can obtain certificates directly from public providers like Let’s Encrypt using tools such as Certbot, which you install and run on your instance.