[RFCI-Discuss] Returning 250 with User Unknown

[Jamie L. Penman-Smithson]

I've encountered a few mail servers (all running Merak) which are  
returning 250 for recipients even when they don't exist - without  
returning any bounce message:

220 get.z-get.com ESMTP Merak 7.4.5; Mon, 17 Apr 2006 11:49:19 -0400
HELO rivendell.silverdream.org
250 get.z-get.com Hello rivendell.silverdream.org [62.3.223.135],  
pleased to meet you.
MAIL FROM:<>
250 2.1.0 <>... Sender ok
RCPT TO:<postmaster at z-get.com>
250 2.1.5 <postmaster at z-get.com>... User unknown

RFC 2821 states that if the recipient is accepted, 250 should be  
returned:
    "If accepted, the SMTP server returns a 250 OK reply and stores the
    forward-path.  If the recipient is known not to be a deliverable  
address,
    the SMTP server returns a 550 reply, typically with a string such as
    "no such user - " and the mailbox name (other circumstances
    and reply codes are possible)."
[..]
    "If an SMTP server has accepted the task of relaying the mail and
    later finds that the destination is incorrect or that the mail  
cannot
    be delivered for some other reason, then it MUST construct an
    "undeliverable mail" notification message and send it to the
    originator of the undeliverable mail"

There is no bounce, so it would seem that they are accepting anything  
and everything and not sending any bounces. AFAICS this is in  
violation of the RFCs, since they are required to notify the sender  
if they are unable to deliver the message to the intended recipient.

Am I right? Or not..

-j
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