Re: Sender header?

[prj@po.cwru.edu (Paul Jarc)]

Stainless Steel Rat <ratinox@peorth.gweep.net> writes:
> * prj@po.cwru.edu (Paul Jarc)  on Fri, 25 May 2001
>| Right (although it also requires help from the server named in the MX
>| record - even if that server accepts mail, it doesn't necessarily
>| accept mail addressed to arbitrary domains).
> 
> But the server mail.foo.com does not accept mail for arbitrary domains, it
> accepts mail for foo.com and those domains it controls.

It may.  Or it may not, depending on what the admin wants.  Nothing is
necessarily broken with a server that accepts mail addressed to
foo.com but rejects mail addressed to bar.foo.com.

>| But who says I want to receive such mail anyway?  If all the addresses I
>| use have "@domain.com", then I can expect that no one will send mail
>| addressed to blah.domain.com, so I have no need to bother with extra MX
>| records.
> 
> Because that is not how the real world works, except in dotcomville where
> the namespace is flat.

And RFC 2822 applies to dotcomville just as everywhere else.  I'm not
saying that accepting mail for subdomains is a bad or uncommon
practice.  I'm just saying it's not required by any RFC, and it isn't
necessary in all situations.

>| I see nothing in 2822 to suggest that Sender should indicate the host
>| where a message originated.  If you do, please point it out.
> 
> It doesn't, because a message's sender has absolutely nothing to do with
> where the message originated.

But you would require Gnus to use the hostname where the message
originated, right?  You've said this is a consequence of *some*
requirement of 2822; show it to us.

>| The string "prj@multivac" is generated by the grammar for "mailbox".
> 
> It is not an RFC 2822 mailbox.

I would agree that RFC probably doesn't intend to include such strings
as mailboxes, but I'm not certain it accomplishes that goal.  The
grammar alone certainly isn't enough to do it.

>| If the requirement for a FQDN is somewhere else, I missed it.
> 
> You missed it.  From RFC 2822 section 3.4.1:
> 
>   "In the domain-literal form, the domain is interpreted as the literal
>   Internet address of the particular host."
> 
> A "literal Internet address" of a host is its local host name, a dot, and
> the local domain name.

Wrong.  You're trying to apply too much intelligence - the "address"
is just that; you don't have to figure out what they really meant (in
this case).  E.g., "prj@[129.22.4.2]".  Anyway, this is just one
possible form of address; requirements on one form don't necessarily
apply to other forms of addresses.

> A mailbox is type addr-spec.  addr-spec is `local-part "@" domain'.
> domain is `dot-atom / domain-literal / obs-domain'.

And dot-atom matches "foo".  In order to require an internal dot via
the grammar, this rule:
  dot-atom-text   =       1*atext *("." 1*atext)
would have to be replaced with:
  dot-atom-text   =       1*atext 1*("." 1*atext)

> Colloquially, a mailbox is local-part@fqdn (less the root dot).

Colloquially, yes.


paul