Re: Email System Model
David MacQuigg wrote:
Alessandro Vesely wrote:
I had hoped that a protocol for configuring forwarding would have
smoothly lent itself to also configure secondary MXes
The model at http://open-mail.org/MHSmodels.html is an
administrative-level model, not a relay-level model. We are modeling
Actors (Users and Agents) and their roles in an email system. Backup
MXs are relays under the control of the Receiving Agent, even if they
are actually subcontracted to a hosting service in another city.
It only makes sense to reserve a place for backup MXes in a model if
such modeling is aimed at bettering the mail system, rather than
merely describing how it currently does [not] work.
To add a Backup Agent to the model, I would need to see an example of
how this might make a difference to any Actor interacting with the
Receiving Agent. Yes, there are many problems with backup MXs not
having current information on a sender's greylist status, not knowing
when the primary MX is back in operation, etc., but how is that
different than a Receiver Agent that simply fumbles its internal
Externally administered backup MXes run into backscattering because
they don't maintain a copy of the users database. To amend that status
of affairs implies that a user's email address will also be stored at
an externally controlled backup MX. Such situation should interest the
users, as those addresses are part of their personally identifiable
information. I say /should/ because the same is true for forwarding.
In both cases, Actors should provide means for exercising their users'