Bill schrieb:


> Just got done figuring out why I wasn't getting non delivery reports
> from some servers. In this case it was two different exchange servers I
> was sending e-mail to non existent accounts and I wasn't getting
> notified of the fact that the message couldn't be delivered. I did a
> network capture and found out that exchange was accepting the messages
> and then would connect back to xmail and try to send the non delivery
> report with MAIL FROM:<>

> I set AllowNullSender to 1 and now I get the returned messages. No
> telling how many messages my users have sent to exchange servers with
> typos in the To: address and didn't know they were not delivered.

There was a thread some days ago talking about the requirement that an
MTA needs to allow MAIL FROM: <> for exact that reason.  If your server
is blocking those messages you will not get notified...this should be
default and users may not alter this setting though XMail's server.tab
allows it.

The thread:

> This may be the RFC requirement that you are looking for: RFC1123 5.2.9
> http://www.ietf.org/rfc/rfc1123.txt

> "5.2.9 Command Syntax: RFC-821 Section 4.1.2 The syntax shown in RFC-821 
> for the MAIL FROM: command omits the case of an empty path: "MAIL FROM: <>" 
> (see RFC-821 Page 15). An empty reverse path MUST be supported."

Ah, I see, but I don't want to allow it... Hmmm, makes it not easier to
fight Spam...

> I believe it may be to do with rejected and bounced messages and return
> receipts

Yes (same RFC):
5.3.3  Reliable Mail Receipt

[...]
         If there is a delivery failure after acceptance of a message,
         the receiver-SMTP MUST formulate and mail a notification
         message.  This notification MUST be sent using a null ("<>")
         reverse path in the envelope; see Section 3.6 of RFC-821.  The
         recipient of this notification SHOULD be the address from the
         envelope return path (or the Return-Path: line).  However, if
         this address is null ("<>"),  the receiver-SMTP MUST NOT send a
         notification.  If the address is an explicit source route, it
         SHOULD be stripped down to its final hop.


Gerrit
-- 
=^..^=

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