DNS & Security Utilities

DNS CAA Record Generator

Build compliant Certification Authority Authorization DNS records. Restrict SSL issuances to trusted providers and configure alerts.

System administrators, DevOps engineers, and security specialists need to publish CAA configurations to secure their domain namespaces. This visual builder constructs syntax-compliant BIND record strings without manual formatting errors. When to use it: When setting up web servers, purchasing wildcard SSL keys, or implementing domain security audits. What it solves: Prevents unauthorized CAs from issuing certificates and flags SSL policy violations. Why it matters: CAA checks are mandatory for all public certificate authorities to protect domains from spoofing.

CAA Settings

Domain Name

Critical Flag

Wildcard Specific CA (issuewild)

Violation Reporting Email/URL (iodef)

BIND / DNS Zone Record Format

General DNS Settings Table

Host	Type	Flag	Tag	Value

How DNS CAA Checking Works

This builder generates BIND zone outputs and parameter lists. The validation logic compiles critical flags and domain parameters into text records.

A CAA DNS record contains three properties: a flag integer, a tag directive, and a quoted value string. When you request an SSL key, the certificate authority queries DNS starting from the subdomain up to the root. If they find a CAA record, they scan the value field matching their domain ID (e.g. letsencrypt.org). If their identifier is missing, the CA aborts issuance, preventing rogue SSL keys from being generated.

Before & After CAA Implementation Examples

❌ Before (No CAA record published)

No CAA rules exist. Any trusted certificate authority worldwide can issue certificates for your domain.

example.com. IN CAA ?
;; No records found. Any CA can issue SSL keys.

✅ After (Active Let's Encrypt authorization)

Publishing CAA records blocks unauthorized authorities, ensuring Let's Encrypt is the sole issuer.

example.com. IN CAA 0 issue "letsencrypt.org"
example.com. IN CAA 0 iodef "mailto:security@example.com"

Industry Use Cases

Developer Workflows	SEO Strategies	Operations & Teams
Lock down wildcard certificate issuance to specific company authorities.	Audit domain configuration records to ensure seamless SSL renewals and prevent site offline periods.	Enforce domain security policies during company mergers.
Generate BIND configurations for automated DNS deployments.	Verify CAA configurations on subdomains before launching micro-sites.	Configure security email alerts to track unauthorized certificate requests.

Common CAA Configuration Mistakes

Locking out Subdomains

Publishing a CAA record at the root domain restricts all subdomains. If subdomains use Amazon Trust but the root only authorizes Let\'s Encrypt, subdomain SSL renewals will fail.

Typoing Certificate Authority Identifiers

Writing the CA name instead of their official domain ID (e.g. writing value="Let\'s Encrypt" instead of value="letsencrypt.org") will make the record invalid, locking out issuance.

DNS CAA Best Practices

Authorize Backup CAs: Always authorize at least one backup CA to prevent site offline delays if your primary CA suffers a service outage.
Configure issuewild: Declare separate issuewild tags if you want to restrict wildcard keys to a different CA.
Publish iodef Reports: Add an email or URL endpoint under the iodef tag to receive alerts about fake issuance attempts.
Verify Subdomain Chains: Check DNS propagation carefully before triggering new SSL certificate requests.

Frequently Asked Questions

What is a DNS CAA record and why is it important?

A CAA (Certification Authority Authorization) record is a type of DNS record that allows domain owners to specify which Certificate Authorities (CAs) are authorized to issue SSL/TLS certificates for their domain. Implementing CAA records prevents unauthorized or rogue CAs from issuing certificates for your domain, protecting you from man-in-the-middle attacks and subdomain hijacking.

Are CAA record checks mandatory for Certificate Authorities?

Yes, as of September 2017, the CA/Browser Forum made CAA record checks mandatory for all publicly trusted Certificate Authorities. Before any CA can issue an SSL certificate, they must query the DNS records of the domain. If a CAA record is published and the requesting CA is not listed, the CA must refuse to issue the certificate.

What is the difference between issue, issuewild, and iodef tags?

The "issue" tag authorizes a CA to issue both wildcard and non-wildcard certificates for the domain. The "issuewild" tag specifically defines CAs authorized to issue wildcard certificates, overriding any "issue" directives for wildcard requests. The "iodef" tag specifies an email address or URL where CAs should report policy violations or unauthorized issuance attempts.

What does the critical flag 0 or 128 mean in a CAA record?

The flag parameter (typically 0 or 128) defines CA behavior for unsupported tags. Flag "0" indicates non-critical; if a CA does not understand a custom tag in your record, it can ignore it and proceed. Flag "128" indicates critical; if a CA does not understand the tag, it must refuse to issue any certificate, providing an extra layer of security.

How do I authorize multiple Certificate Authorities?

To authorize multiple CAs, you must publish multiple separate CAA records in your DNS zone file. For example, if you use both Let's Encrypt and Amazon Trust Services, you publish one CAA record for letsencrypt.org and a second, separate CAA record for amazon.com. A domain can host as many CAA records as needed.

What happens if I publish an empty CAA record set?

If you publish a CAA record containing no authorized CAs (e.g. only containing report tags or blank values), you effectively lock down your domain, instructing ALL certificate authorities that they are not allowed to issue certificates for your site. This is a common security lockdown measure for inactive domains.

How do I publish the CAA record to my DNS provider?

Log in to your DNS registrar dashboard (like Cloudflare, Route 53, or Namecheap), add a new DNS record, select the type "CAA", set the Host/Name to "@" (representing your root domain), choose the appropriate tag (issue, issuewild, or iodef), enter the CA domain (e.g. letsencrypt.org) as the value, and select flag 0 or 128.