Bill Cole wrote:
1. There is no working global mechanism for identifying an accountable
party (i.e. one who explicitly *accepts* accountability) from an IP
address, due largely to the political and historical variations in how
IP addresses have been allocated.
At a first glance, this may seem a flaw in the rDNS/whois systems.
Upon reconsideration, I realize I have no means to accept
accountability for an IP address of mines, since SPF or CSV/CSA only
convey authorization for using a name. In facts, we don't even have
a term for "the accountable party related to an IP address".
Dave's Email Arch mentions an Originator as "accountable for the
message content", but doesn't relate it to an IP address. Rfc5068
associates accountability after submission with traceability
features of the MSA, apparently suggesting that the first relaying
thereafter is from an IP which is (indirectly) accountable for the
message content. Reasoning by induction on the hops, one may
conclude that all relays using a smarthost are accountable:
smarthosts require either IP/firewall configuration or
authentication (assuming they are not open relays.) Accountability
breaks at the MX-driven relay, often referred as "boundary".
Funneling email through MSA systems run by providers that in principle
have some means of holding their users accountable and are capable of at
least understanding bad behavior in mail if not always keeping it
controlled is the best partial workaround we have, and it implies the
need for domain-level accountability or its equivalent.
Why is it partial?
"Domain-level accountability" is a good approximation. However, a
smarthost is not necessarily within the same domain (e.g. ukisp.com
is not even in the same 1st level domain) or the same organization.
How does accountability degrade through indirection? That is, would
you trust an SMTP client the same if it relays on behalf of some
other party?
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