On Thu, Jul 04, 2002 at 09:08:02PM +0100, Richard Kimber wrote:
| On Thu, 4 Jul 2002 14:01:24 -0500
| Derrick 'dman' Hudson <dman@dman.ddts.net> wrote:
|
| > Now when you send mail out, there is both a message and an envelope.
| > The message consists of headers and a body. The message headers don't
| > necessarily match the envelope -- particularly if .forward files are
|
| Your exposition was very helpful for someone like me wanting to understand
| a bit more about email.
Thank you.
| Two (a bit OT) questions:
| 1) Is there a recommened book that details all this?
Philip Hazel wrote a book on exim that is published by O'Reilly. It's
supposed to be very good. (If it's anything like the free
documentation or Philip's mailing list posts, it is good) He's
currently working on a new edition to cover exim 4 (which has changed
a bit, but for the better).
If you want a dead-trees book, now, that covers exim3, go buy it.
Otherwise wait for the exim4 edition to be published, and/or read the
online documentation and join the mailling list. The book is more of
a step-by-step or tutorial style whereas the online documentation (eg
spec.txt) is meant more as a reference for those who already
understand the email/SMTP process.
| 2) How do I get to see the envelope?
1) look at the log (/var/log/exim/mainlog)
2) add these options to your transport that does the delivery :
return_path_add
envelope_to_add
You'll get an extra Envelope-To: header (which will always be your
address, unless you look at someone else's mailstore) and a
Return-Path: header which will be the envelope sender.
| (I ask this because I've recently received some non-spam emails that
| were intended for other people, and my sysadmin pointed out that the
| "From:" and "To:" lines in mail messages can bear no relationship to
| the sender or recipient. So I guess the envelopes were wrong.)
No, the message headers were wrong, and the envelope sender was likely
wrong. It is common for a spammer not to customize each message to
have the correct address in the To:/Cc: header. It is just as common
for them to for the From: and/or envelope sender addresses. About the
only correct piece of data there is the envelope recipient (you).
Exim has an option to perform syntax checks and reject any invalid
message. This works great on some spammers who can't even put a
syntactically valid To: header in the message. It also slams outhouse
users who attempt to Bcc you (because that outhouse puts a
syntactically invalid To: header on the message, unless an actual
address is first included in the To: header by the user).
-D
--
Many a man claims to have unfailing love,
but a faithful man who can find?
Proverbs 20:6
http://dman.ddts.net/~dman/
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