Re: [ietf-smtp] Make username optional in email addresses

[Tim Wicinski <[e-mail]>]

Scott

I have some domains where I would not mind the *@example.com, but most of
them I have a curated list of addresses I want to receive mail to, and the
rest can go away.  I'm curious where folks think the usage level would be.

tim


On Wed, Feb 22, 2023 at 3:46 PM Scott Antipa <[e-mail]> wrote:

> I was thinking this would be a single special email per domain, eg “
> [e-mail]” or whatever. Does that address the scaling problem?
>
> On Fri, Feb 17, 2023 at 6:25 PM John C Klensin <[e-mail]> wrote:
>
>>
>>
>> --On Friday, February 17, 2023 17:30 -0500 tjw ietf
>> <[e-mail]> wrote:
>>
>> > Speaking as a simple dns person
>> >
>> > _role.example.com TXT [e-mail]
>> >
>> > Is my fuel for the discussion
>>
>> Tim,
>>
>> There are at least three issues there (or with something similar
>> using SRV records).
>>
>> One, which may not apply to the smaller, more personal, domains
>> I think Scott is most concerned about, is that sometimes the
>> process of modifying a DNS record involves different people
>> and/or procedures than modifying an email delivery MTA.
>>
>> Second, it is typically going to means three DNS lookups to
>> identify an email address and where to send it, one for the
>> _role record as shown, one to get the MX record(s) for the
>> target domain, and, unless one gets lucky and the addresses of
>> the servers identified in the MX records show up as additional
>> information, a third (or more) to retrieve the addresses for
>> that server or servers.
>>
>> And third, as I think was mentioned in another context, every
>> time that someone has proposed something that might involve a
>> DNS entry per person rather than per host or pseudo-host, the
>> conclusion has been that it would not scale properly.  Now
>> Scott's situation may be a bit different because I think he is
>> thinking about one email address per domain (or, if there were,
>> using the terminology of my earlier note, an "owner" and an
>> "all" one, two).  That might therefore not trigger the scaling
>> problem.  But, still...
>>
>> Whether one did it with a special name and DNS entry or a "role"
>> email address, I think the problem is the same" either the user
>> or the originating MUA needs to understand the naming or RR
>> convention and how to use it.  Then, with Scott's proposal, the
>> delivery server and everything in between need to understand a
>> now-prohibited address and the delivery server needs to
>> understand what it means.  With my  "owner" suggestion, the
>> delivery server has to have an alias for the correct/target
>> address (not unlike the usual treatment for "Postmaster"); with
>> yours the address on the wire is actually the target address.
>>
>> And, Scott, please pay attention to Nathaniel's comment.  Many
>> of us who "own" dedicated domains of which we are the only
>> important user use a multitude of email addresses to organize
>> materials, set up special security mechanisms, and so on.   I
>> don't know about Nathaniel, but I use subaddress mechanisms and
>> probably use hundreds of different addresses.  Some get special
>> post-delivery routing, others don't, and the rules change
>> frequently (in my case, it is rare for a week to go by without
>> my making at least one internal or routing or classification
>> change).  For us, "[e-mail]" or "[e-mail]"
>> would be just one more of those specialized addresses to put in
>> the relevant tables, tables that we need to maintain anyway.
>> Keeping in mind that "@gmail" would almost certainly either have
>> to be rejected or treated as a synonym for something
>> Postmaster-like and that at least some of the cases of
>> @personaldomain.example would be used as Nathaniel and I use
>> them, it is not clear to me that there would actually be
>> significant demand for "@example.com" even if you could get it
>> adopted.
>>
>> best,
>>    john
>>
>>