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AWS AmazonECS documentation change

Service: AmazonECS · 2025-10-01 · Documentation low

File: AmazonECS/latest/developerguide/task-networking.md

Summary

Added comprehensive documentation for IPv6-only VPC configurations in ECS, including network mode updates, regional support, load balancer requirements, and container instance configuration details

Security assessment

While the changes add security-relevant information about configuring security groups with IPv6 rules and network hardening, there's no evidence this addresses a specific security vulnerability. The updates primarily document new IPv6 networking capabilities rather than patching weaknesses. Security documentation additions relate to standard security group configuration practices for a new feature.

Diff

diff --git a/AmazonECS/latest/developerguide/task-networking.md b/AmazonECS/latest/developerguide/task-networking.md
index 4f4d5756d..ab4eda15d 100644
--- a//AmazonECS/latest/developerguide/task-networking.md
+++ b//AmazonECS/latest/developerguide/task-networking.md
@@ -5 +5,3 @@
-# Amazon ECS task networking options for the EC2 launch type
+Using a VPC in IPv6-only mode
+
+# Amazon ECS task networking options for EC2
@@ -13 +15 @@ Network mode | Linux containers on EC2 | Windows containers on EC2 | Description
-`awsvpc` |  Yes |  Yes |  The task is allocated its own elastic network interface (ENI) and a primary private IPv4 address. This gives the task the same networking properties as Amazon EC2 instances.  
+`awsvpc` |  Yes |  Yes |  The task is allocated its own elastic network interface (ENI) and a primary private IPv4 or IPv6 address. This gives the task the same networking properties as Amazon EC2 instances.  
@@ -22,0 +25,110 @@ For more information about Docker networking on Windows, see [Windows container
+## Using a VPC in IPv6-only mode
+
+In an IPv6-only configuration, your Amazon ECS tasks communicate exclusively over IPv6. To set up VPCs and subnets for an IPv6-only configuration, you must add an IPv6 CIDR block to the VPC and create new subnets that include only an IPv6 CIDR block. For more information see [Add IPv6 support for your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-migrate-ipv6-add.html) and [Create a subnet](https://docs.aws.amazon.com/vpc/latest/userguide/create-subnets.html) in the _Amazon VPC User Guide_.
+
+You must also update route tables with IPv6 targets and configure security groups with IPv6 rules. For more information, see [Configure route tables](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Route_Tables.html) and [Configure security group rules](https://docs.aws.amazon.com/vpc/latest/userguide/working-with-security-group-rules.html) in the _Amazon VPC User Guide_.
+
+The following considerations apply:
+
+  * You can update an IPv4-only or dualstack Amazon ECS service to an IPv6-only configuration by either updating the service directly to use IPv6-only subnets or by creating a parallel IPv6-only service and using Amazon ECS blue-green deployments to shift traffic to the new service. For more information about Amazon ECS blue-green deployments, see [Amazon ECS blue/green deployments](./deployment-type-blue-green.html).
+
+  * An IPv6-only Amazon ECS service must use dualstack load balancers with IPv6 target groups. If you're migrating an existing Amazon ECS service that's behind a Application Load Balancer or a Network Load Balancer, you can create a new dualstack load balancer and shift traffic from the old load balancer, or update the IP address type of the existing load balancer.
+
+For more information about Network Load Balancers, see [Create a Network Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/network/create-network-load-balancer.html) and [Update the IP address types for your Network Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/network/load-balancer-ip-address-type.html) in the _User Guide for Network Load Balancers_. For more information about Application Load Balancers, see [Create an Application Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/create-application-load-balancer.html) and [Update the IP address types for your Application Load Balancer](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-ip-address-type.html) in the _User Guide for Application Load Balancers_.
+
+  * IPv6-only configuration isn't supported on Windows. You must use Amazon ECS-optimized Linux AMIs to run tasks in an IPv6-only configuration. For more information about Amazon ECS-optimized Linux AMIs, see [Amazon ECS-optimized Linux AMIs](./ecs-optimized_AMI.html).
+
+  * When you launch a container instance for running tasks in an IPv6-only configuration, you must set a primary IPv6 address for the instance by using the `--enable-primary-ipv6` EC2 parameter.
+
+###### Note
+
+Without a primary IPv6 address, tasks running on the container instance in the host or bridge network modes will fail to register with load balancers or with AWS Cloud Map.
+
+For more information about the `--enable-primary-ipv6` for running Amazon EC2 instances, see [run-instances](https://docs.aws.amazon.com/cli/latest/reference/ec2/run-instances.html) in the _AWS CLI Command Reference_.
+
+For more information about launching container instances using the AWS Management Console, see [Launching an Amazon ECS Linux container instance](./launch_container_instance.html).
+
+  * By default, the Amazon ECS container agent will try to detect the container instance's compatibility for an IPv6-only configuration by looking at the instance's default IPv4 and IPv6 routes. To override this behavior, you can set the ` ECS_INSTANCE_IP_COMPATIBILITY` parameter to `ipv4` or `ipv6` in the instance's `/etc/ecs/ecs.config` file.
+
+  * Tasks must use version `1.99.1` or later of the container agent. For information about how to check the agent version your instance is using and updating it if needed, see [Updating the Amazon ECS container agent](./ecs-agent-update.html).
+
+  * For Amazon ECS tasks in an IPv6-only configuration to communicate with IPv4-only endpoints, you can set up DNS64 and NAT64 for network address translation from IPv6 to IPv4. For more information, see [DNS64 and NAT64](https://docs.aws.amazon.com/vpc/latest/userguide/nat-gateway-nat64-dns64.html) in the _Amazon VPC User Guide_.
+
+  * AAmazon ECS workloads in an IPv6-only configuration must use Amazon ECR dualstack image URI endpoints when pulling images from Amazon ECR. For more information, see [Getting started with making requests over IPv6](https://docs.aws.amazon.com/AmazonECR/latest/userguide/ecr-requests.html#ipv6-access-getting-started) in the _Amazon Elastic Container Registry User Guide_.
+
+###### Note
+
+Amazon ECR doesn't support dualstack interface VPC endpoints that tasks in an IPv6-only configuration can use. For more information, see [Getting started with making requests over IPv6](https://docs.aws.amazon.com/AmazonECR/latest/userguide/ecr-requests.html#ipv6-access-getting-started) in the _Amazon Elastic Container Registry User Guide_.
+
+  * Amazon ECS Exec isn't supported in an IPv6-only configuration.
+
+
+
+
+### AWS Regions that support IPv6-only mode for Amazon ECS
+
+You can run tasks in an IPv6-only configuration in the following AWS regions that Amazon ECS is available in:
+
+  * US East (Ohio)
+
+  * US East (N. Virginia)
+
+  * US West (N. California)
+
+  * US West (Oregon)
+
+  * Africa (Cape Town)
+
+  * Asia Pacific (Hong Kong)
+
+  * Asia Pacific (Hyderabad)
+
+  * Asia Pacific (Jakarta)
+
+  * Asia Pacific (Melbourne)
+
+  * Asia Pacific (Mumbai)
+
+  * Asia Pacific (Osaka)
+
+  * Asia Pacific (Seoul)
+
+  * Asia Pacific (Singapore)
+
+  * Asia Pacific (Sydney)
+
+  * Asia Pacific (Tokyo)
+
+  * Canada (Central)
+
+  * Canada West (Calgary)
+
+  * China (Beijing)
+
+  * China (Ningxia)
+
+  * Europe (Frankfurt)
+
+  * Europe (London)
+
+  * Europe (Milan)
+
+  * Europe (Paris)
+
+  * Europe (Spain)
+
+  * Israel (Tel Aviv)
+
+  * Middle East (Bahrain)
+
+  * Middle East (UAE)
+
+  * South America (São Paulo)
+
+  * AWS GovCloud (US-East)
+
+  * AWS GovCloud (US-West)
+
+
+
+
@@ -29 +141 @@ To use the Amazon Web Services Documentation, Javascript must be enabled. Please
-Best practices for task sizes
+Host network mode