Delivery Status Notification Confirmations

[Fred]

Why does Enterprise not support Delivery Status Notification (DSN) ie: sending a notification to the sender as to whether the message is able to be delivered at the time of the SMTP transaction? "Will it be implemented and if not why not?

[MailEnable-Ian]

Hi,

MailEnable does support bounce messages when a message is temporarily delayed or fails to be delivered. Are you experiencing problems? Can you provide more detail.

[Fred]

Does it support delivery confirmation? If an emailer sends an email to mail enabled server requesting delivery receipt can they be sent a confirmation. I know about non delivery but I want to know about delivery confirmation such as that given when email sent to an exchange server or blackberry device.

[Fred]

yes? no?

[MailEnable-Ben]

As outlined in this article Delivery receipts are only available to Exchange servers;

http://support.microsoft.com/kb/192929

This may have been changed and the implementation requirements have been released but we have not looked into it. If you are making a purchase based on this feature then I would not expect it to be released in the short term (next 4 months).

There is an internal issue in our register for this to be reviewed and possibly implemented at a later date.

[MailEnable]

Further to this, whilst the capability has not formally been released, you can enable it via the following key:

Key Root: HKLM\SOFTWARE\Mail Enable\Mail Enable\CONNECTORS\SMTP
Value Name: DSN Status
Value Type: DWORD
Value: 0/Missing = Off, 1 = On

The change should have the following effect:

1. MailEnable will advertise that it supports DSN to connecting SMTP clients
2. MailEnable will collect and internally route DSN flags throughout the system.
3. MailEnable will generate DSN responses according to the NOTIFY rule supplied by the connecting SMTP client.
4. Messages sent/relayed to downstream SMTP servers that advertise the DSN capability will be passed the DSN flags for processing.

As far as we are aware there are no stability problems associated with the feature, but if you should experience any problems, then I suggest removing the registry key or setting its value to zero.

[Fred]

Thanks for the reg info... I am happy to say I have already purchased enterprise 4 last month

[Fred]

above does not sadly work

[MailEnable]

Hi Fred,

I did unfortunately forget to give you the details of how to advertise the extension.

Code: Select all

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Mail Enable\Mail Enable\Connectors\SMTP\Extensions\DSN]
"Code"="DSN"
"Status"=dword:00000001
"Data"=""

Its effectiveness is contingent on the capabilities of all upstream smtp agents/ or the mailer itself (in that they will need to support the DSN extension).

I tested with Outlook IMAP and it will request DSN notifications.
As far as I could tell, Thunderbird and Outlook Express do not have any capability for requesting Delivery Status Notifications.

Here is what the SMTP log file will look like when a delivery receipt is requested using Outlook:
::1 RCPT RCPT TO: <User@example.com> NOTIFY=SUCCESS,FAILURE,DELAY

The extension is outlined in more detail here: http://www.ietf.org/rfc/rfc3461.txt

[Fred]

Ahh... I used the RegKey of: DSN Status

Shall try your new version

[Fred]

Can you clarify one last thing...

Tue Nov 17, 2009 3:30 am
Key Root: HKLM\SOFTWARE\Mail Enable\Mail Enable\CONNECTORS\SMTP
Value Name: DSN Status

Sat Nov 21, 2009 11:43 pm
Key Root: HKLM\SOFTWARE\Mail Enable\Mail Enable\Connectors\SMTP\Extensions\
Value Name: DSN

I assume your latest post is correct as to where the key DSN is added?

[MailEnable-Ben]

You will need both of the registry modifications posted.

The first one posted enables the feature.

The second (reg export file contents) posted makes sure the smtp service to advertise the extension.

Without the second, clients will not know that the server supports the DSN extension.

EDIT: After some testing, the following is also relevant:
MailEnable's postoffice connector will of course generate delay and failure DSN messages, but will not generate success messages.
This is (most likely) because it could create backscatter spam; but it is a limitation in the current implementation. It will however pass the DSN flags onto remote servers for them to handle the response (which I think covers the scenario you mention).

[Fred]

Add the above two registry "hacks" and did not work... I want it so that if someone sends an email to one of my local hosted mailboxes with a "request for delivery receipt" from Outlook, then when they send the mail and it is sucessfully delivered to my server they get an email back similar to if you send such an email to a Gmail account e.g.

E.G.

If I send an email to a Gmail user and request for delivery receipt then I get the following back from Gmail when sucessfully delivered:

From: Auser@googlemail.com
To: me@localhost.com
Subject: Delivered: Subject heading
Your message was delivered to the recipient.

I also get a txt attachement entitled: details.txt which contains:
Original-Message-ID:98
Final-Recipient:Auser@gmail.com
Action:Delivered



What I want is a similar message sent if a user emails one of my local users and requests a delivery receipt

[Fred]

EDIT: After some testing, the following is also relevant:
MailEnable's postoffice connector will of course generate delay and failure DSN messages, but will not generate success messages.
This is (most likely) because it could create backscatter spam; but it is a limitation in the current implementation. It will however pass the DSN flags onto remote servers for them to handle the response (which I think covers the scenario you mention).

So will this be implemented on Mail Enable Servers? i.e. generate a success message?

[MailEnable]

The outbound delivery should have instructed gmail to deliver a response (ie: the only scenario that should not have worked given the keys i posted is a success notification generated by the mailenable postoffice connector).

Here is why gmail may not have generated the notification.

It seems that gmail does not *always* advertise the DSN extension, and therefore, mailenable's outbound smtp will not pass on the DSN instuction.

Example of smtp capability from gmail inbound smtp agent:

220 mx.google.com ESMTP 34si5232444vws.18
ehlo
250-mx.google.com at your service, [218.214.22.124]
250-SIZE 35651584
250-8BITMIME
250-ENHANCEDSTATUSCODES
250 PIPELINING

Example of smtp capability from mailenable inbound smtp agent:


220 mailenable.com ESMTP MailEnable Service, Version: --4.17 ready at 12/02/09 2
3:53:53
ehlo
250-mailenable.com [218.214.22.124], this server offers 6 extensions
250-AUTH LOGIN
250-SIZE 20120000
250-DSN
250-HELP
250-AUTH=LOGIN
250 STARTTLS

I would guess that perhaps gmail offers a premium service for business customers where it supports DSNs, and thats how your posted notification was generated. Notibly, the gmail client does not seem to even allow you to request a dsn.

I suspect the reason they do not advertise and make it available to the masses is because DSNs can be easily abused by spammers (which is why we prevented the postoffice connector from generating success notifications).

Consider that a spammer may address a message (with a forged from address) to a mail server that supports DSN.
The success notification will be dispatched to the forged sender address with the tainted subject and message details inclusive.
Spam filtering and blocking will prevent some of this, but none-the-less, in a hosted environment, it could cause some significant pain.

I have requested that the the success notification be re-instated and generated provided the DSN status registry keys (mentioned in this thread) are enabled.
It should be available as a minor version update to version 4.