Posted on September 14, 2026 by Nico Vibert and Donia Chaiehloudj, Cilium Cilium 1. 20, the second major open source Cilium release of 2026 after Cilium 1. Three themes stand out in this release: Thank you to every contributor, reviewer and maintainer who made Cilium 1. 20 possible, including engineers from Datadog, Google, Microsoft and many other organisations across the Cilium community. One of the final gaps that stopped us from claiming feature parity across IPv4 and IPv6 in Cilium is gone.
It even makes a footnote in Chapter 4 of Cilium: Up and Running redundant, and while we are a little sad that a note in the book is obsolete so soon after publication, we are glad that ENI mode on AWS finally supports IPv6, four years after the feature request was first raised. Up until now, running Cilium in AWS ENI IPAM mode (the AWS-specific mode that gives pods real VPC addresses) was only possible on IPv4. Now, as a beta feature in Cilium 1. 20, ENI IPAM can allocate and hand out IPv6 as well.
The operator attaches an IPv6 /80 prefix to each node's ENI through Prefix Delegation (which we covered in detail in an earlier blog on how to overcome IP address exhaustion in Kubernetes ), and the agent assigns pod addresses from it. Pods on EKS then boot up dual-stack with VPC-routable IPv6: And here is the other side of it in the AWS console: the /80 IPv6 prefix delegated to a worker node's ENI. The IPv6 address from the first pod above comes straight out of this 2a05:d01c:38d:4c02:909e::/80 range.
Kudos to the folks at Datadog, one of the most impactful organizations contributing to Cilium for years now, for building ENI IPv6 support and finally closing that gap. Watch the video for a short demo. If you'd like to learn more about this feature, check the documentation for more information. In our post covering netkit , we described the newer pod network device as "The Final Frontier in Container Networking Performance".