On Thu, May 10, 2001 at 03:55:16PM -0500, Mate Wierdl wrote:
> A bit offtopic:
>
> A subscriber regularly gets warning messages whenever a certain guy
> posts to the list. This poster has this
>
> From: Francisco Stefano Wechsler <[EMAIL PROTECTED]>
>
> The domain wechsler.fca.unesp.br is nonexistent, and the subscriber's
> ISP (TU-Berlin.DE) has the policy that if there is no valid sender
> address in any header field, they bounce the message. Hence the
> message bounces back to ezmlm, which then sends a probe to the
> subscriber.
>
> Is there any rfc that is violated by TU-Berlin.DE's policy?
Quotes from RFC2821 (which replaces RFC821):
When RFC 822 format [7, 32] is being used, the mail data include the
memo header items such as Date, Subject, To, Cc, From. Server SMTP
systems SHOULD NOT reject messages based on perceived defects in the
RFC 822 or MIME [12] message header or message body. In particular,
they MUST NOT reject messages in which the numbers of Resent-fields
do not match or Resent-to appears without Resent-from and/or Resent-
date.
----
As discussed in section 2.4.1, a relay SMTP has no need to inspect or
act upon the headers or body of the message data and MUST NOT do so
except to add its own "Received:" header (section 4.4) and,
optionally, to attempt to detect looping in the mail system (see
section 6.2).
[note: section 2.4.1 doesn't exist in RFC2821, nor in RFC821]
--
recipients buffer
The minimum total number of recipients that must be buffered is
100 recipients. Rejection of messages (for excessive recipients)
with fewer than 100 RCPT commands is a violation of this
specification. The general principle that relaying SMTP servers
MUST NOT, and delivery SMTP servers SHOULD NOT, perform validation
tests on message headers suggests that rejecting a message based
on the total number of recipients shown in header fields is to be
discouraged.
Sounds like a SHOULD NOT. However, the general principle this last
quote refers to, doesn't seem to be mentioned specifically anywhere.
Greetz, Peter.
