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Module: route53-resolver-dns-firewall

Terraform module to provision Route 53 Resolver DNS Firewall, domain lists, firewall rules, rule groups, and logging configurations.

Usage​

For a complete example, see examples/complete

For automated tests of the complete example using bats and Terratest (which tests and deploys the example on AWS), see test.

provider "aws" {
  region = var.region
}

module "vpc" {
  source  = "cloudposse/vpc/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"

  ipv4_primary_cidr_block                   = "172.19.0.0/16"
  dns_hostnames_enabled                     = true
  dns_support_enabled                       = true
  internet_gateway_enabled                  = false
  ipv6_egress_only_internet_gateway_enabled = false
  assign_generated_ipv6_cidr_block          = false

  context = module.this.context
}

module "s3_log_storage" {
  source  = "cloudposse/s3-log-storage/aws"
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"

  force_destroy = true
  attributes    = ["logs"]

  context = module.this.context
}

module "route53_resolver_firewall" {
  # Cloud Posse recommends pinning every module to a specific version
  # version     = "x.x.x"

  vpc_id = module.vpc.vpc_id

  firewall_fail_open        = "ENABLED"
  query_log_enabled         = true
  query_log_destination_arn = module.s3_log_storage.bucket_arn

  domains_config = {
    "not-secure-domains" = {
      # The dot at the end of domain names is required by Route53 DNS Firewall
      # If not added, AWS adds it automatically and terraform shows permanent drift
      domains = [
        "not-secure-domain-1.com.",
        "not-secure-domain-2.com.",
        "not-secure-domain-3.com."
      ]
    },
    "alert-domains" = {
      domains = [
        "alert-domain-1.com.",
        "alert-domain-2.com.",
        "alert-domain-3.com."
      ]
    },
    "blacklisted-domains" = {
      # Concat the lists of domains passed in the `domains` field and loaded from the file `domains_file`
      domains = [
        "blacklisted-domain-1.com.",
        "blacklisted-domain-2.com.",
        "blacklisted-domain-3.com."
      ]
      domains_file = "config/blacklisted_domains.txt"
    }
  }

  rule_groups_config = {
    "not-secure-domains-rule-group" = {
      # 'priority' must be between 100 and 9900 exclusive
      priority = 101
      rules = {
        "block-not-secure-domains" = {
          # 'priority' must be between 100 and 9900 exclusive
          priority                  = 101
          firewall_domain_list_name = "not-secure-domains"
          action                    = "BLOCK"
          block_response            = "NXDOMAIN"
        }
      }
    },
    "alert-and-blacklisted-domains-rule-group" = {
      # 'priority' must be between 100 and 9900 exclusive
      priority = 200
      rules = {
        "alert-domains" = {
          # 'priority' must be between 100 and 9900 exclusive
          priority                  = 101
          firewall_domain_list_name = "alert-domains"
          action                    = "ALERT"
        },
        "block-and-override-blacklisted-domains" = {
          # 'priority' must be between 100 and 9900 exclusive
          priority                  = 200
          firewall_domain_list_name = "blacklisted-domains"
          action                    = "BLOCK"
          block_response            = "OVERRIDE"
          block_override_dns_type   = "CNAME"
          block_override_domain     = "go-here.com"
          block_override_ttl        = 1
        }
      }
    }
  }

  context = module.this.context
}

Variables​

Required Variables​

domains_config required

Map of Route 53 Resolver DNS Firewall domain configurations

Type:

map(object({
domains      = optional(list(string))
domains_file = optional(string)
}))

rule_groups_config required

Rule groups and rules configuration

Type:

map(object({
priority            = number
mutation_protection = optional(string)
# https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/route53_resolver_firewall_rule
rules = map(object({
  action                    = string
  priority                  = number
  block_override_dns_type   = optional(string)
  block_override_domain     = optional(string)
  block_override_ttl        = optional(number)
  block_response            = optional(string)
  firewall_domain_list_name = string
}))
}))

vpc_id (string) required

VPC ID

Optional Variables​

firewall_fail_open (string) optional

Determines how Route 53 Resolver handles queries during failures, for example when all traffic that is sent to DNS Firewall fails to receive a reply.
By default, fail open is disabled, which means the failure mode is closed.
This approach favors security over availability. DNS Firewall blocks queries that it is unable to evaluate properly.
If you enable this option, the failure mode is open. This approach favors availability over security.
In this case, DNS Firewall allows queries to proceed if it is unable to properly evaluate them.
Valid values: ENABLED, DISABLED.



Default value: "ENABLED"

query_log_config_name (string) optional

Route 53 Resolver query log config name. If omitted, the name will be generated by concatenating the ID from the context with the VPC ID


Default value: null

query_log_destination_arn (string) optional

The ARN of the resource that you want Route 53 Resolver to send query logs.
You can send query logs to an S3 bucket, a CloudWatch Logs log group, or a Kinesis Data Firehose delivery stream.



Default value: null

query_log_enabled (bool) optional

Flag to enable/disable Route 53 Resolver query logging


Default value: false

Context Variables​

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id.
This is for some rare cases where resources want additional configuration of tags
and therefore take a list of maps with tag key, value, and additional configuration.


Required: No

Default value: { }

attributes (list(string)) optional

ID element. Additional attributes (e.g. workers or cluster) to add to id,
in the order they appear in the list. New attributes are appended to the
end of the list. The elements of the list are joined by the delimiter
and treated as a single ID element.


Required: No

Default value: [ ]

context (any) optional

Single object for setting entire context at once.
See description of individual variables for details.
Leave string and numeric variables as null to use default value.
Individual variable settings (non-null) override settings in context object,
except for attributes, tags, and additional_tag_map, which are merged.


Required: No

Default value:

{
  "additional_tag_map": {},
  "attributes": [],
  "delimiter": null,
  "descriptor_formats": {},
  "enabled": true,
  "environment": null,
  "id_length_limit": null,
  "label_key_case": null,
  "label_order": [],
  "label_value_case": null,
  "labels_as_tags": [
    "unset"
  ],
  "name": null,
  "namespace": null,
  "regex_replace_chars": null,
  "stage": null,
  "tags": {},
  "tenant": null
}
delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.


Required: No

Default value: null

descriptor_formats (any) optional

Describe additional descriptors to be output in the descriptors output map.
Map of maps. Keys are names of descriptors. Values are maps of the form
\{<br/> format = string<br/> labels = list(string)<br/> \}
(Type is any so the map values can later be enhanced to provide additional options.)
format is a Terraform format string to be passed to the format() function.
labels is a list of labels, in order, to pass to format() function.
Label values will be normalized before being passed to format() so they will be
identical to how they appear in id.
Default is {} (descriptors output will be empty).


Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

Limit id to this many characters (minimum 6).
Set to 0 for unlimited length.
Set to null for keep the existing setting, which defaults to 0.
Does not affect id_full.


Required: No

Default value: null

label_key_case (string) optional

Controls the letter case of the tags keys (label names) for tags generated by this module.
Does not affect keys of tags passed in via the tags input.
Possible values: lower, title, upper.
Default value: title.


Required: No

Default value: null

label_order (list(string)) optional

The order in which the labels (ID elements) appear in the id.
Defaults to ["namespace", "environment", "stage", "name", "attributes"].
You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.


Required: No

Default value: null

label_value_case (string) optional

Controls the letter case of ID elements (labels) as included in id,
set as tag values, and output by this module individually.
Does not affect values of tags passed in via the tags input.
Possible values: lower, title, upper and none (no transformation).
Set this to title and set delimiter to "" to yield Pascal Case IDs.
Default value: lower.


Required: No

Default value: null

labels_as_tags (set(string)) optional

Set of labels (ID elements) to include as tags in the tags output.
Default is to include all labels.
Tags with empty values will not be included in the tags output.
Set to [] to suppress all generated tags.
Notes:
The value of the name tag, if included, will be the id, not the name.
Unlike other null-label inputs, the initial setting of labels_as_tags cannot be
changed in later chained modules. Attempts to change it will be silently ignored.


Required: No

Default value:

[
  "default"
]
name (string) optional

ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.
This is the only ID element not also included as a tag.
The "name" tag is set to the full id string. There is no tag with the value of the name input.


Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

Terraform regular expression (regex) string.
Characters matching the regex will be removed from the ID elements.
If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.


Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.


Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs​

domains

Route 53 Resolver DNS Firewall domain configurations

query_log_config

Route 53 Resolver query logging configuration

rule_group_associations

Route 53 Resolver DNS Firewall rule group associations

rule_groups

Route 53 Resolver DNS Firewall rule groups

rules

Route 53 Resolver DNS Firewall rules

Dependencies​

Requirements​

  • terraform, version: >= 1.0
  • aws, version: >= 5.0

Providers​

  • aws, version: >= 5.0

Modules​

NameVersionSourceDescription
this0.25.0cloudposse/label/nulln/a

Resources​

The following resources are used by this module:

Data Sources​

The following data sources are used by this module: