Guide: Network Configuration by Region

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Guide: Network Configuration by Region

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Guide: Network Configuration by Region

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Guide: Network Configuration by Region

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{{InANutshell|
<li>Each bwCloud-OS instance launched using the standard method is automatically assigned a public IP address.</li>
<li> Floating IPs, which persist independent of instances, are also available.
</li>
<li>Instances are also assigned a persistent FQDN based on their name, project and region.</li>
<li>Domain hosting is not provided, but you can point your own domain to the instance’s FQDN using a CNAME record.</li>
}}

__TOC__

= Networks & IP-addresses =

== Will my instance receive a public IP? ==


By default every VM receives a '''public''' '''IPv6''' address. It also receives a '''private''' '''IPv4''' address, so that '''egress IPv4''' connectivity is provided via '''SNAT'''.

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

'''Note:''' IPv4 ingress connectivity ('''public IPv4'''-addresses) can also be provided in every region via a [https://bw-support.scc.kit.edu/ support ticket].

[[Guide:_Public_IPv4_Allocation_in_Regions|➡️ A detailed guide to public IPv4 allocation in regions]]

== 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 persist even after an Instance deletion. They can be released manually.

== Are Floating IPs also available for instances? ==


Yes.

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

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

➡️ [[Guide: Routers and Floating IPs|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., <code>ma</code> for Mannheim)
* The '''domain suffix''': <code>.bw-cloud-instance.de</code>

'''Example:'''

If your instance name is <code>kos</code>, the project is called <code>yarn</code> and it runs in Mannheim (<code>ma</code>), the FQDN will be:<pre>kos.yarn.vm.ma.bwcloud-os-instance.de</pre>The FQDN can also be found in the '''[https://portal.bw-cloud.org/ 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 <code>bwcloud-os-instance.de.</code> 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 ====
Since the FQDN is persistent for the instance's lifetime (even if the instance is stopped and started again), you can safely set a CNAME record like:

<code>myvm.example.org → instance-name.project-name.vm.region.bwcloud-os-instance.de</code>

==== 🔹 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.