Re: Make username optional in email addresses

Scott Antipa <[email protected]> Wed, 22 Feb 2023 10:46:28 -1000
Newsgroups gmane.ietf.smtp
Message-ID <CAG6nNWdZgn=maXtscsN3c_6HwJh_CnuqwfDq=LJEc97DTU54sQ@mail.gmail.com>
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I was thinking this would be a single special email per domain, eg =E2=80=
=9C
[email protected]=E2=80=9D or whatever. Does that address the scaling pr=
oblem?

On Fri, Feb 17, 2023 at 6:25 PM John C Klensin <[email protected]> wrote:

>
>
> --On Friday, February 17, 2023 17:30 -0500 tjw ietf
> <[email protected]> wrote:
>
> > Speaking as a simple dns person
> >
> > _role.example.com TXT [email protected]
> >
> > 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, "[email protected]" or "[email protected]"
> 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
>
>

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<div dir=3D"auto">I was thinking this would be a single special email per d=
omain, eg =E2=80=9C<a href=3D"mailto:[email protected]">catchall@example=
.com</a>=E2=80=9D or whatever. Does that address the scaling problem?</div>=
<div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">O=
n Fri, Feb 17, 2023 at 6:25 PM John C Klensin &lt;<a href=3D"mailto:john-ie=
[email protected]">[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"=
gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-=
left:1ex"><br>
<br>
--On Friday, February 17, 2023 17:30 -0500 tjw ietf<br>
&lt;<a href=3D"mailto:[email protected]" target=3D"_blank">tjw.ietf@gmail.=
com</a>&gt; wrote:<br>
<br>
&gt; Speaking as a simple dns person<br>
&gt; <br>
&gt; _<a href=3D"http://role.example.com" rel=3D"noreferrer" target=3D"_bla=
nk">role.example.com</a> TXT <a href=3D"mailto:[email protected]" target=
=3D"_blank">[email protected]</a><br>
&gt; <br>
&gt; Is my fuel for the discussion <br>
<br>
Tim,<br>
<br>
There are at least three issues there (or with something similar<br>
using SRV records).=C2=A0 <br>
<br>
One, which may not apply to the smaller, more personal, domains<br>
I think Scott is most concerned about, is that sometimes the<br>
process of modifying a DNS record involves different people<br>
and/or procedures than modifying an email delivery MTA.=C2=A0 <br>
<br>
Second, it is typically going to means three DNS lookups to<br>
identify an email address and where to send it, one for the<br>
_role record as shown, one to get the MX record(s) for the<br>
target domain, and, unless one gets lucky and the addresses of<br>
the servers identified in the MX records show up as additional<br>
information, a third (or more) to retrieve the addresses for<br>
that server or servers.<br>
<br>
And third, as I think was mentioned in another context, every<br>
time that someone has proposed something that might involve a<br>
DNS entry per person rather than per host or pseudo-host, the<br>
conclusion has been that it would not scale properly.=C2=A0 Now<br>
Scott&#39;s situation may be a bit different because I think he is<br>
thinking about one email address per domain (or, if there were,<br>
using the terminology of my earlier note, an &quot;owner&quot; and an<br>
&quot;all&quot; one, two).=C2=A0 That might therefore not trigger the scali=
ng<br>
problem.=C2=A0 But, still...<br>
<br>
Whether one did it with a special name and DNS entry or a &quot;role&quot;<=
br>
email address, I think the problem is the same&quot; either the user<br>
or the originating MUA needs to understand the naming or RR<br>
convention and how to use it.=C2=A0 Then, with Scott&#39;s proposal, the<br=
>
delivery server and everything in between need to understand a<br>
now-prohibited address and the delivery server needs to<br>
understand what it means.=C2=A0 With my=C2=A0 &quot;owner&quot; suggestion,=
 the<br>
delivery server has to have an alias for the correct/target<br>
address (not unlike the usual treatment for &quot;Postmaster&quot;); with<b=
r>
yours the address on the wire is actually the target address.<br>
<br>
And, Scott, please pay attention to Nathaniel&#39;s comment.=C2=A0 Many<br>
of us who &quot;own&quot; dedicated domains of which we are the only<br>
important user use a multitude of email addresses to organize<br>
materials, set up special security mechanisms, and so on.=C2=A0 =C2=A0I<br>
don&#39;t know about Nathaniel, but I use subaddress mechanisms and<br>
probably use hundreds of different addresses.=C2=A0 Some get special<br>
post-delivery routing, others don&#39;t, and the rules change<br>
frequently (in my case, it is rare for a week to go by without<br>
my making at least one internal or routing or classification<br>
change).=C2=A0 For us, &quot;<a href=3D"mailto:[email protected]" target=3D=
"_blank">[email protected]</a>&quot; or &quot;<a href=3D"mailto:everyone@ex=
ample.com" target=3D"_blank">[email protected]</a>&quot;<br>
would be just one more of those specialized addresses to put in<br>
the relevant tables, tables that we need to maintain anyway.<br>
Keeping in mind that &quot;@gmail&quot; would almost certainly either have<=
br>
to be rejected or treated as a synonym for something<br>
Postmaster-like and that at least some of the cases of<br>
@personaldomain.example would be used as Nathaniel and I use<br>
them, it is not clear to me that there would actually be<br>
significant demand for &quot;@<a href=3D"http://example.com" rel=3D"norefer=
rer" target=3D"_blank">example.com</a>&quot; even if you could get it<br>
adopted.<br>
<br>
best,<br>
=C2=A0 =C2=A0john<br>
<br>
</blockquote></div></div>

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