Cannot ping ec2 instances in the same private subnet

Question

I have two EC2 instances in the same private subnet. I am trying to ping the IP of one EC2 instance to the other instance but getting timeout issues.

Both instances are added to a security group. The rules of this security group are:

Inbound - All Traffic - All Traffic - <VPC CIDR>
Outbound- All Traffic - All Traffic - <VPC CIDR>

On the private subnet, there are net ACLs but these have inbound and outbound rules for:

All Traffic - All Traffic - <VPC CIDR>

I would have expected to be able to ping the each of the EC2 instances that are in the same private subnet given the rules that I added.

Is there some other rule that I am missing?

Do instances within the subnet require anything else to allow communication between the instances?

Edit: Answer The Windows firewall rules on the machine were preventing pinging between the instances. This was disabled to confirm it was the case, with the necessary rules added later.

Answer 1

You have to allow all ICMP traffic in your security group definition. See https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html#sg-rules-ping