Request for assistance
John Abreau
jabr at abreau.net
Tue Dec 17 23:19:48 EST 2002
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Content-Type: text/plain; charset=us-ascii
John Chambers <jc at trillian.mit.edu> writes:
> This isn't consistent with the behavior that I've seen on ANY unix
> system. The most common MTA, the /bin/mail program, always has a -v
> option that shows you the transaction. In most cases, what it shows
> you is an immediate connection to the remote system, followed by the
> SMTP conversation. When this finishes, the email has been delivered,
> and no local server was involved.
Not exactly. /bin/mail *always* pipes the message to a local instance
of sendmail. The -v option is merely passed to the sendmail command line
as it's invoked, and the transaction you see is coming from sendmail.
> If this fails for some reason (e.g., you're offline), you get a line
> saying that the message has been queued. This merely means that it is
> sitting in a directory (usually /var/spool/mail) on your disk. It has
> not been handed to a server of any sort.
The sendmail instance is being started by the /bin/mail process. It's
not talking via SMTP to a preexisting sendmail daemon that's listening
on port 25, so in that sense it's not talking to a "server". Regardless,
it *is* still handing the message off to sendmail.
> If you don't have a full-time connection, you do need a server on
> some fully-connected machine for incoming mail. (The UUCP folks had a
> solution to this, but the SMTP gang never learned about it. ;-) You
> still don't need a local server for outgoing mail. And in the usual
> unix setup, you don't use one.
The SMTP folks long ago defined "batched SMTP", which would write the
SMTP transaction into a file, and then the sysadmin setting up the
mail service would be responsible for devising a mechanism to transport
such files to a better-connected peer. As I recall, it didn't see much
use, mainly because people who needed that functionality were already
using sendmail over UUCP to achieve store-and-forward mail transport.
- --
John Abreau / Executive Director, Boston Linux & Unix
Email jabr at blu.org / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9
PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.7 (GNU/Linux)
Comment: Exmh version 2.5 07/13/2001
iQCVAwUBPf/3Y1V9A5rVx7XZAQLMbAQAjb7O4TDwFMIXH+mBsejnNAqiYmshwQUy
Re2KGMY6oQHeuh5DxCWiPsXBs0l8u8mK0pf54uCrTk9khMSGSyPFEppTQa1/Xs6J
rtxw+kzPlaTt0rfp/GYwDvn/0eH6DJr5pw/i1cbwG1+HvdgmY9YGqBoXLOYzUptZ
F7btHrllhqk=
=/4FF
-----END PGP SIGNATURE-----
More information about the Discuss
mailing list