A mailing list is a mediator (at the User level), not a relay at the SMTP
THen what about autoforwarders with access controls?
It *is* the "host specified in the domain part of the address". So it should
interpret the local part.
Of the recipient address, sure. But not the originator address.
When I send this message to ietf-smtp(_at_)imc(_dot_)org, only imc.org knows
interpret the local part. RFC 5321 is not in conflict with reality, at least
in this example.
When you send mail to ietf-smtp(_at_)imc(_dot_)org, a check is made to see if
subscriber to the list. I doubt that your address is in imc.org and that check
is probably done in a case-insensitive way.
Replace ietf-smtp(_at_)imc(_dot_)org with an autoforwarder with access control,
RFC 5321 *is* in conflict with reality.
Ned, I am not quite following.
Isn't this implementation specific?
I think the "smith" vs "Smith" idea is old, but I think the key idea
is about preservation as stated in 2.4:
Therefore, SMTP implementations MUST take care to preserve the case
of mailbox local-parts.
The SMTP receiver should not be forcing it one way or another - just
store as is up to the point where it doesn't matter any more. But it
still implementation specific and I don't see where in 5321 it says a
"comparison" must be case sensitive. That wouldn't be reality.
Its not just about compares, but rendering as well, as well as replies.
For our system this was all very important as our old school online
hosting system started out as a local hosting system only (a BBS).
So we still have
- single name vs first last name account system.
older setups still force names upper case.
- default dot/undot formatting
"name" <--> "name" <name(_at_)domain(_dot_)com>
"First Last" <--> "First Last" <first(_dot_)last(_at_)domain(_dot_)com>
"First I. Last" <--> "First I. Last"
- Some remaining parts of the software and many of the
3rd party tools still used upper case user names.
"OLD USER" <--> "OLD USER" <old(_dot_)user(_at_)domain(_dot_)com>
- Some mail readers STILL force upper case, like an still
popular 16 bit reader that forces the TO/FROM to uppercase
in the wire transmission.
- Some of the older multi-network gating force the case.
But on the inbound side, it is all preserved but all compares are case
in-sensitive. What happens after that, depends on what the software
is, how old, if its a 3rd party etc.