3.1. ADSP Applicability 4.3. ADSP Lookup Procedure Verify Domain Scope:
This draft imposes a requirement that a domain within a From email- address is to be found within DNS. This requirement is intended to provide a domain control over the ADSP default assertions made below their name hierarchy. However, excluding domains without known TLDs could be inappropriate as well. What is also excluded from this draft is a definition for specific protocols where the domains are expected to be supported. NNTP might use a TLD of .invalid to ensure an address is not mistaken for a valid email-address. Micros~1 Exchange permits use of X.400 email-addresses aliased to a domain name assigned via their registry without existing within DNS. In addition, there is nothing within this draft to suggest that the ADSP assertions are limited to messages publicly exchanged over SMTP port 25. This draft should warn ADSP DKIM signature expectations may affect other protocols converted and then bridged into SMTP, or those received over other protocols by MUAs. In addition, the suggestion to use wildcard domains to publish ADSP TXT records necessitates exclusion of domains without valid host name syntax. This draft tangentially refers to RFC2821, but only with respect to case-insensitivity. Do not expect wildcard domains will defend against chosen-name.*.example.com, or chosen- name._domainkey.example.com, for example. These exploits can be prevented by insuring valid host name syntax. Add: ADSP defines a record that can advertise the extent to which a domain signs outgoing mail that is publicly exchanged on SMTP port 25, as described in [RFC2821]. Also, how other hosts can access those records. Advertisements, defined by this document, may also increase DKIM signature expectations for messages received by Mail User Agents (MUAs) or for messages which might have been exchanged over protocols other than SMTP. In some circumstances, author domains may wish to have accommodations for protocol failures or for mixed public protocol messaging not to be made. -Doug _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
