2. Let's add IPv6 CIDRs to Subnets

- Click on"Your VPCs”

- Select the displayed Default VPC.

- Click Actions and choose “Edit CIDRs”

- Click Add IPv6 CIDR.

- You’ll notice that a new IPv6 CIDR would be added to the VPC. Verify the successful association and click on “close”

Let’s add IPv6 CIDRs to Subnets

- Select a subnet and from “Actions” choose “Edit IPv6 CIDRs”

- This will present you a new page to add Subnet CIDR block to the subnet along with existing IPv4 CIDR. Enter a value Hexadecimal value between 00 - FF in the input box for the subnet and click “Save”.

- Once IPv6 CIDR has been successfully associated, click “Close” on the screen to revert back to list of Subnets in VPC.

- Repeat the process for all subnets. Once all AZs/Subnets have IPv6 CIDR successfully added, subnets would look like this:

- Now, let’s review Network ACLs for the IPv6 enabled subnets:

- You’ll notice that NALCs are also update with IPv6 Source & Destination (::/0) which should allow traffic to pass IN/OUT of the subnets.