Email Portability Approved by Knesset Committee

James Hess mysidia at gmail.com
Mon Feb 22 19:35:10 CST 2010


On Mon, Feb 22, 2010 at 10:30 AM, Jeff Kell <jeff-kell at utc.edu> wrote:
> There's no way to do this without some underlying forwarding...  and

Forwarding SMTP traffic consumes major bandwidth resources
(potentially), as the number of 'ports' eventually increases, and
seems like a juicy target for many different types of potential
abuses.  There are major technical hurdles that should be considered,
otherwise ISPs  probably wouldn't care much to provide mailboxes,  and
instead: might simply recommend an overseas service (not subject to
the port rules)  for people who want e-mail.

Or include "purchase of a domain name"  in the price of getting e-mail
service, it's just another "tax" required due to government
regulations,  ISP/telephone/cable subscribers are already used to
those types of fees.    When the end user purchases their own domain,
it's up to them to transfer their own domain name  and deal with all
the technical issues that entails.


Issues like: spam against forwarded addresses (impossible to reliably
implement SPF and other sending MTA based protections).   Possibility
of the "porting mail server" being blacklisted (interfering with
forwarding), having,  sketchy connectivity, or other  persistent
issues,  or  low message size limits  "No more than a 500mb attachment
can be forwarded",  that might have been the reason the user switched
e-mail providers in the first place,  so they could receive  30gb
HD-DVD ISOs  their friends were e-mailing them.....


Resolving the   destination address is what DNS is for,  not what SMTP
routing is for.
Perhaps there is...  Give every e-mail user a subdomain as in
examplemailbox at examplemailbox.example.com

To  "port" an e-mail address,    the   receiving ISP  then provides a
domain name server for the donor ISP  to publish as in...
mailbox.example.com         IN  NS    theirdns1.example2.com


Use  "IN NS"   subdelegation to the user's  new ISP.  This requires
the ISP to  "plan for portability",  by designating  a subdomain for
each user,  and having DNS software that can handle (potentially)
hundreds of thousands of permanent mailbox records.

For authentication, to request a change,  make it be proven that the
request is coming from a legitimate authority of the host the  "IN NS"
 record points to.



Or else rewrite the SMTP specification to change how the SMTP server
is selected  for every single  e-mail transaction  (assuming the
internet community actually thinks this is worthwhile)....

Instead of merely performing a lookup of MX against just the host
label (where MX exists),   bring in  Mailbox binding

As in  bring back RFC 883 MAILB:
QNAME=mailbox at mx.example.com    QTYPE=MAILB

after a successful response from a QTYPE=MX query.
If  NXDOMAIN  is returned  from MAILB then proceed to contact  the MX.
But if MR responses arereceived from the MAILB query,  then the
sending MTA should switch to the recipient destination as directed.

And repeat the MX and MAILB lookup process with the new destination...

But the  presence  of a MAILB  record  must  not imply that the e-mail
address likely exists.     The absence must not imply the e-mail
address likely doesn't exist,   either....

Otherwise spammers would be very happy.  ISPs must wildcard MAILBs
or have some very robust abuse-protections in DNS itself,   or
end-users would never want to use     MAILB-based porting.


--
-J




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