DNS Firewall with Fail-Open Stated, Not Inherited
Domain lists, rule group, rules and VPC associations. Fail-open is an availability decision wearing a security name: closed makes a firewall fault a DNS outage, open resolves unfiltered without saying so. The module makes you choose.
Verification
Static-verifiedPassed: validated and lint-clean (provider-schema-validated for AWS/Azure/GCP; Terraform-language lint elsewhere).
Conformance
- Static validation (fmt · validate · tflint)
- Security scan clean (Checkov)
- Plan tests (mocked: validation rules · outputs)
Provenance
- SHA-256 checksum
- Signature (pending)
Functional
- Live test pending (no cloud run yet)
Last verified 2026-09-12 · how we verify
Use it from the registry
terraform · opentofumodule "dns_firewall" {
source = "www.iac-bazaar.com/iac-bazaar/aws-dns-firewall/aws"
version = "1.0.0"
}Needs a registry token from /account/tokens. The module itself is free; the account is what identifies you. Full setup: registry docs.
Cite it in your README
badge · attributionPaste this beside the module in the repository that uses it. The badge is rendered from this artifact's verification record, so it reads static-verified because the record says so, and the link lands on this page.
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Terraform module 1.0.0, static-verified on IaC Bazaar: [DNS Firewall with Fail-Open Stated, Not Inherited](https://www.iac-bazaar.com/catalog/aws-dns-firewall?utm_source=syndication&utm_medium=readme&utm_campaign=artifact)
```hcl
module "dns_firewall" {
source = "www.iac-bazaar.com/iac-bazaar/aws-dns-firewall/aws"
version = "1.0.0"
}
```Preview:
Inputs & outputs
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Documentation
aws-dns-firewall
A Route 53 Resolver DNS Firewall: domain lists, a rule group, its rules, and the
VPC associations that put it in the path. Works with Terraform and OpenTofu
(>= 1.6), AWS provider >= 6.0, < 7.0.
Fail-open is an availability decision wearing a security name, and it is the setting here worth thinking about twice.
fail_open = false(the default, and AWS's) fails a query the firewall cannot evaluate. Nothing unfiltered gets through - and a firewall problem becomes a DNS outage for every host in the VPCfail_open = trueresolves those queries unfiltered. The application keeps working and the control is not applied, without saying so
Neither is wrong. Choosing by accident is, which is why this module states it rather than inheriting it.
An ALERT rule is not a control. It logs the query and resolves it. That is
how you find out what a rule would break before you turn it on, and it is not
protection - the two look the same in the console, so the alert_only_rules
output lists them by name.
Other things it gets right that are easy to get wrong by hand:
example.comand*.example.comare two different entries. There is no leading-dot shorthand, and listing only the bare name leaves every subdomain resolving- Rule priorities are validated unique, in range, and the docs push you toward gaps - inserting between two adjacent priorities means renumbering the rest
mutation_protectionis on: rule groups get detached during incidents by people who mean well- A
BLOCKrule without ablock_response, and anOVERRIDEwithout a domain, are both refused by preconditions rather than by the API several minutes in
Verification
Static validation runs tofu fmt, init, validate, tflint and checkov.
This module has not yet had a live test, so it is published as statically
validated with its live test pending and does not carry the live-tested mark.
Usage code & full reference need an account
The complete copy-paste usage, the full input/output reference, and operational notes are free with an account - shown here and bundled in the download. Sign in and this section fills in.
- Usage
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