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Re: domain names, was: hostname

On Thu 22 Mar 2018 at 22:17:02 (-0000), Dan Purgert wrote:
> David Wright wrote:
> > On Thu 22 Mar 2018 at 08:58:43 (-0400), Greg Wooledge wrote:
> >> [...]
> >> An SMTP receiver SHOULD validate the recipient address right here,
> >> right now.  It SHOULDN'T just accept everything and then figure out
> >> whether it's deliverable later -- that enables joe-job spam.
> >
> > How is it meant to do that. If it's relaying, the system it's
> > eventually going to send the message to might not even be
> > running just now. Email is store and forward, isn't it?
> If it's *relaying*, it is not *receiving*; there's a subtle but key
> difference there.  At most, a relay will likely validate 
>  - source (host or user) is allowed to relay via me.
>  - destination is a FQDN
> The closest that a relay will "store-and-forward" is in essence similar
> to if your roommate (significant other, etc.) is going out ... you say
> "hey, since you're gonna go past the mailbox, mind dropping these in
> there for me?".  That is, it will only "store" the message long enough
> to dump it off at the intended recipient (as defined by the MX Host for
> the target domain).

I took "receiver" to mean the sense used here:
"Message transfer can occur in a single connection between two MTAs, or
in a series of hops through intermediary systems. A receiving SMTP
server may be the ultimate destination, an intermediate "relay" (that
is, it stores and forwards the message) or a "gateway" (that is, it
may forward the message using some protocol other than SMTP). Each hop
is a formal handoff of responsibility for the message, whereby the
receiving server must either deliver the message or properly report
the failure to do so."

Some of us remember when emails passed through several gateways and
could take a couple of days to reach their destination. We used to
spend our time juggling addresses containing multiple ::, @, and %
delimiters, with hops through JANET (which at that time wrote its
addresses backwards), EARN, BITNET and Inmarsat, all kicked off by
pasting the message into a Telex on BT Gold. Academic institutions
could only afford to link up through Inmarsat a couple of times a
day at most. I could only afford BT Gold (out of hours) because a
friend managed an experimental comms project at university. This
was how it was in the mid-late 1980s.

> > [...]
> >
> > My last point may become less true over time because, as I already
> > just posted, there is now an authoritative answer: If you don't
> > know what to put, put home, corp, or mail, as you wish. They are
> > guaranteed never to become TLDs in the future.
> They're as guaranteed to "not" become as TLD as much as ".local" or
> ".me" or ".tech" were guaranteed to "not" be a TLD in the 1990s.

Perhaps this was pre-ICANN? Do you have a reference? Or a contact inside
ICANN that knows something nobody else knows about resolution 2018.02.04.12.

> > I'm not convinced that I, and many in my situation, would be better
> > off running a mail server rather than having an organisation run a
> > smarthost to do it on my behalf. (They also take care of incoming mail
> > by running an IMAP server.)
> Ultimately it depends on how far you trust your ISP.  Cox is pretty good
> (at least they were when I was in their service area).  TWC/Spectrum was
> generally good, but they could break hard.  AT&T (Yahoo) is completely
> useless.
> Also, by running your own mailserver, you are not bound to your ISPs (or
> google's, etc.) size limits / ads / etc.  For example, my parents can
> send me 50MB emails (old and refuse to learn dropbox / owncloud for pics
> of their grandkids ... so they send mails, and I put them where they
> belong).

Yes, it's tedious that Cox sends a marketing letter every week expounding
their TV service. Oh, you didn't mean that? Which ads do you mean?


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