Alleviating Issues with IPv6 Application Communication in AWS VPC
Question
You currently have setup a VPC and subnets in AWS.
You have setup routes in the route table for traffic on the CIDR block of 0.0.0.0/0
You just want to establish communication across all hosts.
But you notice that some applications are not working as desired.
These are Ipv6 based applications that are sitting across subnets in the VPC.
What must be done to alleviate this issue?
Answers
Explanations
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A. B. C. D.Answer - C.
CIDR blocks for IPv4 and IPv6 are treated separately.
For example, a route with a destination CIDR of 0.0.0.0/0 (all IPv4 addresses) does not automatically include all IPv6 addresses.
You must create a route with a destination CIDR of ::/0 for all IPv6 addresses.
For more information on Route propagation , one can visit the below URL:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Route_Tables.htmlIn this scenario, the VPC and subnets have been set up with a route table that includes a route for traffic on the CIDR block of 0.0.0.0/0. This means that all traffic, including IPv6 traffic, will be sent to the Internet Gateway (IGW) for routing.
However, some IPv6-based applications are not working as desired, which suggests that the current routing configuration is not allowing for proper communication across subnets in the VPC.
To alleviate this issue, option C should be selected: add a route for ::/0 to the route table as well. This will enable IPv6 traffic to be properly routed across subnets in the VPC, as well as to the Internet Gateway.
Option A (ensuring a more specific route is placed) and option D (adding the default route of 172.132.0.0/16 to the route table) are not relevant to this scenario, as they do not address the specific issue of enabling communication for IPv6-based applications.
Option B (removing the route of 0.0.0.0/0 and adding the route of ::/0 instead) may seem like a potential solution, but it is not the recommended approach. This is because removing the route of 0.0.0.0/0 would prevent all traffic, including IPv4 traffic, from being routed properly. Therefore, it is better to keep the existing route for IPv4 traffic and simply add a new route for IPv6 traffic (i.e., option C).
