Re: [PLUG] "inter-user mail"

[Tobias DiPasquale <toby@cbcg.net>]

On Thu, 2002-12-05 at 20:13, Thomas Thurman wrote:
> On Thu, 5 Dec 2002, Arthur S. Alexion wrote:
> > I like the idea of using username@localhost.  Will that work given this 
> > other information?
> 
> AFAICS, it shouldn't really make a difference. Because domain-parts can be
> names of hosts, as long as your machine knows that "localhost" is
> itself, any halfway sane MTA should use local delivery for addresses
> ending with it.

Ok, let's finish this: The RFC REQUIRES the domain part for it to be a
valid SMTP address. It requires a user and domain part for ALL SMTP
senders and recipients. In this, it is quite clear. (RFC 822/2822)

If there is no MTA running on the local machine, to get messages
delivered you would use sendmail(1) or a functional equivalent, since
only an MTA running on your local machine would be capable of delivering
a message bound for 'localhost'. (due to DNS) NOTA BENE: When using
sendmail(1) or the like, no SMTP transaction actually takes place in a
local-user to local-user message scenario.

Also, since I've never met a client that was fully-RFC compliant, what
it will do when you give it 'user@localhost' is up to the client.
Evolution will attempt to deliver it to whatever account you specify,
regardless of whether or not you're running an MTA, which is dead wrong.

Bottom line: if you're not running an MTA on the machine, you can only
use sendmail(1), mail(1) or the like, or get your GUI client to use it
for you. Local-user to local-user without a local MTA is not a real SMTP
transaction situation. In this case, the MDA takes on the role of the
MTA and acts as both.

-- 
<< Tobias DiPasquale >>
UNIX Software Engineer
http://cbcg.net/

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