At 10:21 AM -0400 6/20/05, Stefan Jeglinski imposed structure on a
stream of electrons, yielding:
The only way SIMS can deliver is when it gets a legit envelope
address, no? In Eudora, there is a header called x-envelope I can
turn on, but no envelope header appears in received e-mail that I
can tell.
That's not actually Eudora creating that header, but rather Eudora
hiding it if you have it set to hide it. Some MTA's will add that
header.
To clarify, I had indeed removed it from the hidden headers, thus
keeping Eudora from hiding it. As I read your answer, it would then
appear only if the MTA added it to begin with.
Right. And that is rare.
That hints at why there is no standard way to record the envelope
recipient: there can be more than one. Back before spammers made it
useful to shun such mail and before AOL established mystery bounces
as a de facto standard, a lot of mail for mailing lists was
delivered as one copy per domain with multiple envelope recipients
(i.e. RCPT commands in SMTP) to save on bandwidth and delivery
time. This is still sometimes used today but is less common than it
used to be because of the degraded trust and reliability of the
mail system brought on by both conscious abusers (spammers) and by
shoddy mail system design and implementation (e.g. AOL, until the
past couple of years.) SIMS puts a 'for' clause into its Received
header when there is a single envelope recipient, but in the rare
cases where there are multiple recipients it does not do so as a
privacy protection.
So with SIMS, if I see a "for" in the Received header, I know there
was but one envelope recipient (which is also shown). Got it. How
common is this particular behavior in MTAs? Put another way, is the
use of "envelope" as a separate header deprecated or uncommon now?
It has never been particularly common. The 'X-' prefix on a header is
an indication that the header is experimental and not part of the
mail standard or even a formally defined extension to the standard.
How about the insertion of "for"?
Received headers have traditionally been very loosely defined, but
many MTA's will by default act just like SIMS: one RCPT results in a
'for' clause in the Received header.
--
Bill Cole
[EMAIL PROTECTED]
#############################################################
This message is sent to you because you are subscribed to
the mailing list <[email protected]>.
To unsubscribe, E-mail to: <[EMAIL PROTECTED]>
To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]>
To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]>
Send administrative queries to <[EMAIL PROTECTED]>
