AWS Amazon EC2 Network ACL
This page shows how to write Terraform for Amazon EC2 Network ACL and write them securely.
aws_default_network_acl (Terraform)
The Network ACL in Amazon EC2 can be configured in Terraform with the resource name aws_default_network_acl
. The following sections describe 4 examples of how to use the resource and its parameters.
Example Usage from GitHub
resource "aws_default_network_acl" "default" {
default_network_acl_id = var.default_network_acl_id_of_default_vpc
# no rules defined, deny all traffic in this ACL
// https://github.com/hashicorp/terraform/issues/9824
resource "aws_default_network_acl" "default-acl" {
default_network_acl_id = aws_vpc.network.default_network_acl_id
ingress {
rule_no = 100
action = "allow"
resource "aws_default_network_acl" "dev_default" {
default_network_acl_id = aws_vpc.dev.default_network_acl_id
ingress {
protocol = -1
rule_no = 100
resource "aws_default_network_acl" "default" {
provider = "aws.given"
default_network_acl_id = aws_default_vpc.default.default_network_acl_id
}
Parameters
-
arn
optional computed - string -
default_network_acl_id
required - string -
id
optional computed - string -
owner_id
optional computed - string -
subnet_ids
optional - set of string -
tags
optional - map from string to string -
vpc_id
optional computed - string -
egress
set block-
action
required - string -
cidr_block
optional - string -
from_port
required - number -
icmp_code
optional - number -
icmp_type
optional - number -
ipv6_cidr_block
optional - string -
protocol
required - string -
rule_no
required - number -
to_port
required - number
-
-
ingress
set block-
action
required - string -
cidr_block
optional - string -
from_port
required - number -
icmp_code
optional - number -
icmp_type
optional - number -
ipv6_cidr_block
optional - string -
protocol
required - string -
rule_no
required - number -
to_port
required - number
-
Explanation in Terraform Registry
Provides a resource to manage a VPC's default network ACL. This resource can manage the default network ACL of the default or a non-default VPC.
NOTE: This is an advanced resource with special caveats. Please read this document in its entirety before using this resource. The
aws_default_network_acl
behaves differently from normal resources. Terraform does not create this resource but instead attempts to "adopt" it into management. Every VPC has a default network ACL that can be managed but not destroyed. When Terraform first adopts the Default Network ACL, it immediately removes all rules in the ACL. It then proceeds to create any rules specified in the configuration. This step is required so that only the rules specified in the configuration are created. This resource treats its inline rules as absolute; only the rules defined inline are created, and any additions/removals external to this resource will result in diffs being shown. For these reasons, this resource is incompatible with theaws_network_acl_rule
resource. For more information about Network ACLs, see the AWS Documentation on [Network ACLs][aws-network-acls].
Tips: Best Practices for The Other AWS Amazon EC2 Resources
In addition to the aws_default_vpc, AWS Amazon EC2 has the other resources that should be configured for security reasons. Please check some examples of those resources and precautions.
aws_default_vpc
Ensure to avoid using default VPC
It is better to define the own VPC and use it.
aws_network_acl_rule
Ensure your network ACL rule blocks unwanted inbound traffic
It is better to block unwanted inbound traffic.
aws_ebs_volume
Ensure to use a customer-managed key for EBS volume encryption
It is better to use a customer-managed key for EBS volume encryption. It can be gain more control over the encryption by using customer-managed keys (CMK).
aws_instance
Ensure to avoid storing AWS access keys in user data
It is better to avoid storing AWS access keys in user data. `aws_iam_instance_profile` could be used instead.
aws_security_group
Ensure your security group blocks unwanted inbound traffic
It is better to block unwanted inbound traffic.
CloudFormation Example
CloudFormation code does not have the related resource.
Frequently asked questions
What is AWS Amazon EC2 Network ACL?
AWS Amazon EC2 Network ACL is a resource for Amazon EC2 of Amazon Web Service. Settings can be wrote in Terraform.
Where can I find the example code for the AWS Amazon EC2 Network ACL?
For Terraform, the purpleteam-labs/purpleteam-iac-sut, seemscloud/terraform-aws-elasticsearch-service and asbubam/2dal-infrastructure source code examples are useful. See the Terraform Example section for further details.