On Thu, 01 Apr 2004 03:19:15 +0000, Blinky the Shark wrote:
> Would you happen to have a handy link to a layman's explanation of this
> envelope concept and what else it entails? At any rate, if I read it
> correctly, the above explanation will save me the headscratching that I
> always do when I get the pink stuff without any To address on it.
I'm not joseph, and I don't have one handy, but I can produce an example
right quick. The following is a short example transcript with an SMTP
server (mine, as it happens):
server>220 machinae.lionsanctuary.net ESMTP Welcome to
mail.lionsanctuary.net
A welcome banner accepting the new connection with an OK code (2xx) and
advertising the presence of ESMTP as well as vanilla SMTP
client>EHLO eidolon.lionsanctuary.net
eidolon.lionsanctuary.net is the client's hostname, not the server's. EHLO
instead of HELO activates ESMTP; either greeting tells the mail server who
it's talking to.
server>250-machinae.lionsanctuary.net
server>250-PIPELINING
server>250-SIZE 10240000
server>250-VRFY
server>250-ETRN
server>250-XVERP
server>250 8BITMIME
250 is the OK response to EHLO; each line is a single capability on the
server.
client>MAIL FROM:
(E-Mail Removed)
server>250 Ok
This is the envelope FROM address. It may bear no relation to the
message's headers, later.
client>RCPT TO:
(E-Mail Removed)
server>250 Ok
This is the envelope TO address -- the recipient the message is intended
for.
client>DATA
server>354 End data with <CR><LF>.<CR><LF>
Now we've told the server to expect the actual mail message.
client>To:
(E-Mail Removed)
client>Subject: foo bar baz
client>
The mail headers...
client>This is the message body
client>.
server>250 Ok: queued as 11AD02A2B3E
....and the message body, terminated with a . on a line of its own. The
mail server I use provides the queue ID as a courtesy feature, as well
(postfix). Notably the "To:" header in the mail message bears utterly no
resemblance to the envelope TO.
In my case the queue was very short and the message actually arrived
before I typed the next line.
client>QUIT
server>221 Bye
Connection closed.
You can duplicate this sort of exchange yourself by using any plain-text
tool (like telnet; I use netcat) to connect to your SMTP server on port 25.
--
Some say the Wired doesn't have political borders like the real world,
but there are far too many nonsense-spouting anarchists or idiots who
think that pranks are a revolution.
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