RFC 5518, "Vouch By Reference", April 2009Source of RFC: IETF - NON WORKING GROUP
Area Assignment: sec
See Also: RFC 5518 w/ inline errata
Errata ID: 2583
Publication Format(s) : TEXT
Reported By: John Levine
Date Reported: 2010-10-26
Verifier Name: Sean Turner
Date Verified: 2012-01-06
Section 7.1 says:
If the DKIM signature contains an i= field, the domain name from that field is used; otherwise, the domain name from the DKIM signature d= field is used.
It should say:
The domain name from the DKIM signature d= field is used.
RFC 5672 clarifies that the d= domain is the primary identity in a DKIM signature.