CAA

CAA() adds a CAA record to a domain. The name should be the relative label for the record. Use @ for the domain apex.

Tag can be one of

1. "issue"

2. "issuewild"

3. "iodef"

Value is a string. The format of the contents is different depending on the tag. DNSControl will handle any escaping or quoting required, similar to TXT records. For example use CAA("@", "issue", "letsencrypt.org") rather than CAA("@", "issue", "\"letsencrypt.org\"").

Flags are controlled by modifier:

• CAA_CRITICAL: Issuer critical flag. CA that does not understand this tag will refuse to issue certificate for this domain.

dnsconfig.js

D("example.com", REG_MY_PROVIDER, DnsProvider(DSP_MY_PROVIDER),
  // Allow letsencrypt to issue certificate for this domain
  CAA("@", "issue", "letsencrypt.org"),
  // Allow no CA to issue wildcard certificate for this domain
  CAA("@", "issuewild", ";"),
  // Report all violation to [e-mail]. If CA does not support
  // this record then refuse to issue any certificate
  CAA("@", "iodef", "mailto:[e-mail]", CAA_CRITICAL),
END);

DNSControl contains a CAA_BUILDER which can be used to simply create CAA() records for your domains. Instead of creating each CAA record individually, you can simply configure your report mail address, the authorized certificate authorities and the builder cares about the rest.