>If there were a protocol that said "if you receive mail signed by this domain >/ this key and the recipient isn't in >the To: or Cc: field, block it", or some similar protocol that signed the >envelope recipient, that would pretty much >eliminate DKIM replay as a threat in some cases.
It would, but it would also break innocent single message forwarding and cause yet more grief for mailing lists. A remarkable number of the addresses I manage for my church, local town government, and so forth are just forwards to Gmail or the local telco and cable ISPs. You could certainly add workarounds, and in the case of Gmail most of them have set up their Gmail accounts to send mail with the forwarded address so Gmail knows what forwards to expect, but it still adds complexity and fragility. It's not clear that replay attacks are common enough to be worth extra mechanism in potentially every message. R's, John _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
