Email Portability Approved by Knesset Committee
mysidia at gmail.com
Tue Feb 23 01:35:10 UTC 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.
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