iis smtp nntp: How to troubleshoot when the below problem occurred? There is no problem
sending to other email addresses.

The following recipient(s) could not be reached:



user@domain.com on 29/01/08 11:40 AM

You do not have permission to send to this recipient. For
assistance, contact your system administrator.

<smtp02.nafa.edu.sg #5.7.1 smtp;550 5.7.1 Unable to relay for
user@domain.com>

In addition to the previous mail.
user@domain.com sent to my user, my user tried to reply to user@domain.com ,
yet this encountered this problem.


[quoted text, click to view]

[quoted text, click to view]

Incoming SMTP !=3D outgoing SMTP. While there are some anti-abuse=

mechanisms which force a correlation between the two directions of
mailflow, in most respects the two are independent. Don't assume
interaction where the basic protocol doesn't have one.

[quoted text, click to view]

This is self-explanatory. The remote mail server refused to accept
mail, stating it could not relay. That means either [1] the remote
server is the correct MX, but is misconfigured so that it rejects mail
for this user or for the entire domain it is meant to service; [2]
their DNS is serving up incorrect MX records due to inconsistency
across NSs and/or accidental misconfiguration, so you are connecting
perhaps to an auth-only submission, a defunct MX, or a box otherwise
not meant to service the domain; or, also possible, [3] the error
message is incorrect, and you are being blocked by an
anti-spam/anti-abuse system that doesn't customize its error text.

--Sandy




------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.

[quoted text, click to view]

E-mail client applications may send using different accounts depending
on whether a message is a reply or a fresh message. Whether there were
internal users also on the recipient list is usually immaterial to the
account selected.

You also could have observed a simple coincidence based on remote
configuration changes over a short period of time.

If you can replicate those different results, then you have an local
account-selection problem to track down. Otherwise, coincidence.

--Sandy




------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.

Thank for the reply....
The 1st time the user sent/reply to a few internal users and the recipient
(external partner) mentioned below. The external partner email bounced back,
as mentioned below.
I asked the user to send again only to this external party. The email sent
successfully!
How to explained this strange incident???


[quoted text, click to view]

Incoming SMTP != outgoing SMTP. While there are some anti-abuse
mechanisms which force a correlation between the two directions of
mailflow, in most respects the two are independent. Don't assume
interaction where the basic protocol doesn't have one.

[quoted text, click to view]

This is self-explanatory. The remote mail server refused to accept
mail, stating it could not relay. That means either [1] the remote
server is the correct MX, but is misconfigured so that it rejects mail
for this user or for the entire domain it is meant to service; [2]
their DNS is serving up incorrect MX records due to inconsistency
across NSs and/or accidental misconfiguration, so you are connecting
perhaps to an auth-only submission, a defunct MX, or a box otherwise
not meant to service the domain; or, also possible, [3] the error
message is incorrect, and you are being blocked by an
anti-spam/anti-abuse system that doesn't customize its error text.

--Sandy




------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.
------------------------------------