> 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-address/ipv6/overview/limitations.md).

# Limitations

IONOS CLOUD VDC Networking: known limitations for IPv6 in virtual data centers

* One limitation of IPv6 is that a **/56 block** is typically assigned to a data center, with a **/64 block** assigned inside this **/56 block** to the Local Area Network (LAN). The difference between a **/56** and a **/64** block is **8**, resulting in **2^8 (2 to the power of 8) blocks**, or a total of **256 blocks**. This limitation can impact the scalability and flexibility of IPv6 addressing in large networks. Therefore, it is important to carefully consider the allocation of IPv6 blocks to ensure efficient utilization of available resources.
* You will get a new **/56 prefix** every time you create a new data center. If your services depend on static IPv6 addresses, and you want to rebuild your data center, you must not delete the data center itself, but only its components, such as, LANs, NICs, etc. For more information about how to create new Data Center LANs in DCD, see [<mark style="color:blue;">**DCD How-Tos**</mark>](/cloud/network-services/vdc-networking/ip-address/ipv6/how-tos.md).
* For older Debian images (version 10 and version 11), you may need to tweak the OS initialization process of your image. For example, the Dynamic Host Configuration Protocol version 6 (DHCPv6) client may need to be run manually after restarting the system. Generally, if the interfaces have not received an IPv6 address from the <code class="expression">space.vars.ionos\_cloud</code> DHCP server, try to run the DHCPv6 client manually. For more information, see [<mark style="color:blue;">**FAQs**</mark>](/cloud/network-services/vdc-networking/ip-address/ipv6/faqs-ipv6.md).
* In Rocky Linux 8, it is important to note that the IPv6 protocol may not be readily available after the initial boot. For the latest version, Rocky Linux 9.0, you can use IPv6 support right from the first boot.
* Currently, IPv6 is not available for Managed Services such as Application Load Balancer (ALB), Network Load Balancer (NLB), Network Address Translation (NAT) Gateway, IP Failover and Managed Kubernetes (MK8s).


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