[Servercert-wg] SC18: Phone Contact with DNS CAA Phone Contact

Doug Beattie doug.beattie at globalsign.com
Thu Apr 11 13:13:20 MST 2019

Hi Marcelo,


I thought that the method for returning the random Value to the CA could be
left unspecified because it could be done via any method the CA would like
to support.  Options like SMS, email, upload in portal, phone or similar
could be supported, so I just included this: "The Random Value MUST be
returned to the CA to approve the request."  This is consistent with the
other phone validation methods.







From: Silva, Marcelo <masilva at visa.com> 
Sent: Thursday, April 11, 2019 12:42 PM
To: Doug Beattie <doug.beattie at globalsign.com>; CA/B Forum Server
Certificate WG Public Discussion List <servercert-wg at cabforum.org>
Subject: RE: SC18: Phone Contact with DNS CAA Phone Contact


Hi Doug, I think this is a good addition to the CAA records in regards to
the domain validation options, and we support that.

What's not clear it's that this is actually just an alternative for starting
the validation process, right? Since we eventually will have to continue
getting the confirmation in a written (or digital) form along with the given
random number.

So, should we somehow explicit that in the validation process?




From: Servercert-wg <servercert-wg-bounces at cabforum.org> On Behalf Of Doug
Beattie via Servercert-wg
Sent: Thursday, April 11, 2019 9:36 AM
To: CA/B Forum Server Certificate WG Public Discussion List
<servercert-wg at cabforum.org>
Subject: [Servercert-wg] SC18: Phone Contact with DNS CAA Phone Contact


Ballot SC18: Phone Contact with DNS CAA Phone Contact

Purpose of Ballot: This ballot will permit domain owners to publish phone
numbers in a DNS CAA record for the purposes of performing domain

The following motion has been proposed by Doug Beattie of GlobalSign and
endorsed Tim Hollebeek of DigiCert and Bruce Morton from Entrust.


This ballot modifies the "Baseline Requirements for the Issuance and
Management of Publicly-Trusted Certificates" as follows, based on Version


Add the following definition to section 1.6.1:

DNS CAA Phone Contact: The phone number defined in section B.1.2.


Add Section as follows: Phone Contact with DNS CAA Phone Contact 

Confirm the Applicant's control over the FQDN by calling the DNS CAA Phone
Contact's phone number and obtain a confirming response to validate the ADN.
Each phone call MAY confirm control of multiple ADNs provided that the same
DNS CAA Phone Contact phone number is listed for each ADN being verified and
they provide a confirming response for each ADN. The relevant CAA Resource
Record Set MUST be found using the search algorithm defined in RFC 6844
Section 4, as amended by Errata 5065 (Appendix A).

The CA MAY NOT be transferred or request to be transferred as this phone
number has been specifically listed for the purposes of Domain Validation.

In the event of reaching voicemail, the CA may leave the Random Value and
the ADN(s) being validated.  The Random Value MUST be returned to the CA to
approve the request.

The Random Value SHALL remain valid for use in a confirming response for no
more than 30 days from its creation. The CPS MAY specify a shorter validity
period for Random Values.  

Note: Once the FQDN has been validated using this method, the CA MAY also
issue Certificates for other FQDNs that end with all the labels of the
validated FQDN.  This method is suitable for validating Wildcard Domain


Add appendix section B.1.2 as follows:

B.1.2. CAA contactphone Property

SYNTAX: contactemail <rfc3966 Global Number> 

The CAA contactphone property takes a phone number as its parameter.  The
entire parameter value of the MUST be a valid Global Number as defined in
RFC 3966 section 5.1.4, or it cannot be used.  Global Numbers MUST have a
preceding + and a country code and MAY contain visual separators.

The following is an example where the holder of the domain specified the
contact property using a phone number.

$ORIGIN example.com.

    CAA 0 contactphone "+1 (555) 123-4567"

The contactphone property MAY be critical if the domain owner does not want
CAs who do not understand it to issue certificates for the domain.





A comparison of the changes can be found at: 



The procedure for approval of this ballot is as follows:


Discussion (7+ days)


Start Time: 2019-04-11 12:00 Eastern

End Time: Not before 2018-04-18 12:00 Eastern


Vote for approval (7 days)


Start Time: TBD

End Time: TBD


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