Networks

In a Nutshell

Each bwCloud-OS instance automatically receives a public IP address, valid for its entire lifetime (until deletion). Instances are also assigned a persistent FQDN based on their UUID 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?

Yes. By default, every instance launched using the standard method in bwCloud-OS is automatically assigned a publicly accessible IP address.

Each region in bwCloud-OS has its own set of IP address ranges, which may differ from one another. You can find the current public IP ranges for each region here.

How long does an IP remain assigned to my instance?

The public 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.

Are Floating IPs also available for instances?

Currently only in certain regions, such as Freiburg. However, Floating IPs are planned for all regions after the next major software upgrade in 2026.

See the Floating IP Guide for detailed setup instructions.

Hostnames and Domains

Does bwCloud-OS also assign hostnames?

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 FQDN:

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

Example:

If your instance UUID is caffee-4242-2323-caffee and it runs in Mannheim (ma), the the FQDN will be:

caffee-4242-2323-caffee.ma.bw-cloud-instance.org

Retrieval: From inside the instance the FQDN can be determined by:

# BWC_REGION="ma"

# FQDN="$(cat /var/lib/cloud/data/instance-id).${BWC_REGION}.bw-cloud-instance.org"

The FQDN can also be found in the Dashboard, under the instance details

Can I get a domain via bwCloud-OS?

No, we do not offer domain hosting. However, every user is free to enter a CNAME in their home institution or even in any domain that points to the FQDN. Users can also set up DynDNS-like systems outside the cloud, which can be configured to the corresponding IP by their own VMs, similar to the procedure for the home network connection if this is made accessible via a persistent name.

How can I point a domain to an instance?

It should either be done dynamically or via a CNAME record to the FQDN of the VM. The assignment of a UUID to an instance is persistent (permanent), even if the instance is stopped - therefore the CNAME record of a domain can refer to the FQDN.

Can I get a certificate via bwCloud-OS?

No, we do not offer certificates. However, your instance can obtain certificates from other institutions (e.g. Let's Encrypt) using the CertBot.