On 12/1/2015 6:05 AM, Tony Finch wrote:
Ted Lemon <mellon(_at_)fugue(_dot_)com> wrote:
Monday, Nov 30, 2015 6:02 PM Dave Crocker wrote:
On 11/30/2015 2:51 PM, Ted Lemon wrote:
Why would I be relaying mail on? Only for a mailing list.
The most obvious is mailbox aliasing, such as for vanity addresses such
as university alumni associations provide.
That's a mailing list with one subscriber. Same scenario.
Not really. Mailing lists have very different administrative behaviour to
aliases - they change the return path to an administrative address when
forwarding the message whereas aliases do not. RFC 5321 section 3.9.
Yes. And further...
They typically also have very different formal -- that's meant as
'official', not 'math' -- semantics.
Alias behavior tends to be /very/ close to pure relaying. It changes
very little in the message, other than the rfc5321.Rcpt-To address.
Mailing lists tend to make massive changes to the original message; they
are taking formal delivery of the message and then post a new message.
For end users, the view is of a single message from original author to
final recipient. To the email infrastructure it is two (or more)
post/deliver sequences.
Folks seeking to discuss email at this level should consider becoming
familiar with RFC 5598. It will make careful discussion of email
behavior a lot more consistent...
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
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