On Wed, Aug 29, 2007 at 11:54:15AM -0400, Ben Scott wrote: > On 8/29/07, Paul Lussier <[EMAIL PROTECTED]> wrote: > > Or /bin/mail... Technically it is the LDA which does the > > user-existence verification checks, not the MDA. > > An LDA is a type of MDA. Any LDA is also an MDA. > > If you meant "MTA", then again, I point out that an MTA can also > perform address verification, and Sendmail does this "by default" (as > much as any Sendmail behavior can be called a "default" <grin>). If > you don't believe me, connect to TCP/25 on liberty.gnhlug.org and try > RCPT TO:<[EMAIL PROTECTED]>. It will reject it then and there, > before any MDA is invoked.
Then again, any software bundle can play different roles in the delivery of email, and there are a lot of blurry edges between the roles. One might consider the address-verification part of the package we think of as an "MTA" to be done by its role as MDA. Even more pedantically, you can't really tell from telnetting to port 25 exactly what software is being invoked to give you that response. (e.g. if it's postfix, you might be seeing the result of consulting a policy daemon; if it's sendmail, you might be interacting, in part, with a milter.) > > I wouldn't consider POP or IMAP an MUA. How about "protocols" ? :) > *I* wouldn't either. But as far as I know, as far as the RFCs are > concerned, there are MTAs (which move mail around), MDAs (which accept > and process mail for delivery), and MUAs (which handle mail on behalf > of the user). Oh, and MSAs (Message Submission Agent), which is a > subset of SMTP for MUAs that only inject mail. > > > POP and IMAP simply store it until picked up by the authenticated user. > > IMAP typically stores it afterwards, too -- unless your initials are > "pll". ;-) > > > Perhaps 'Mail Storage Agent' ? > > I like it, but it collides with MSA. For all these buzzwords, er, concepts, and more, you might find this: http://www.ietf.org/internet-drafts/draft-crocker-email-arch-09.txt to be enjoyable reading. > > Never say never. Let's all agree that we *hope* we never need to use > > Exchange as an MDA for a postfix or sendmail system! > > Well, I suppose if you had Sendmail or Postfix running on a Exchange > server, and you also wrote a custom MAPI or CDO program to inject mail > into the Exchange Information Store without using the Exchange SMTP > service, then you could do that. Do Exchange boxes offer LMTP services? If so, they could be used as an MDA for a sendmail or postfix server. Even if not, if the postfix or sendmail server is merely handing off delivery to an Exchange server via SMTP, it could easily be considered as making use of the Exchange server as an MDA. (It's the role, not the software..) > I used to work at UNH. Did not know that. So did I, in the dark ages. :) mm _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
