ietf-dkim
[Top] [All Lists]

Re: [ietf-dkim] ISSUE 1573: Modify ADSP Lookup Procedure

2008-06-03 22:39:14

Dave Crocker wrote:
Dave Crocker wrote:
  
Modify ADSP Domain Existence procedure.

Use draft-levine-dkim-adsp-00, Section 4.3. ADSP Lookup Procedure as input 
to 
discussions.
    


Per the Levine draft, this also entails addition of:

      <section anchor="applicability" title="ADSP Applicability">
         <t> ADSP as defined in this document is bound to DNS. For this 
reason,
           ADSP is applicable only to Author Domains with appropriate DNS
           records (see Note below). The handling of other Author Domains is
           outside the scope of this document. However, attackers may use such
           domain names in a deliberate attempt to sidestep an organization's
           ADSP policy statements. It is up to the ADSP verifier 
implementation
           to return an appropriate error result for Author Domains outside 
the
           scope of ADSP. <list style="hanging">
             <t hangText="Note:  "> The results from DNS queries that are
               intended to validate a domain name unavoidably approximate
               the set of Author Domains that can appear in legitimate email.
               For example, a DNS A record could belong to a device that does
               not even have an email implementation. It is up to the verifier
               to decide what degree of approximation is acceptable.</t>


to the Section 3. Operation Overview.
  

At least part of this (what attackers might do) reads like a Security 
Consideration, and perhaps belongs there instead.

I'd like to suggest that we use a different word than "approximate" in 
the above discussion and in the Levine draft.  "Approximate" may give 
the impression that the error may be in either direction, i.e., that 
there may be some legitimate email domains may be considered out of 
scope for ADSP.  How about something like "overestimate" instead?  (Note 
that I'm not considering a hostname like wjvax.UUCP to be a legitimate 
mail domain any more).

-Jim


_______________________________________________
NOTE WELL: This list operates according to 
http://mipassoc.org/dkim/ietf-list-rules.html