Positive DSN if delay_warning_time is reached?

[Florian Pritz]

Hi,

I've currently set delay_warning_time = 4h and maximal_queue_lifetime =
5d, which are nice values and all, but if I get a delay DSN I'd like to
know sooner than after 5 days if the mail went through.

I can't seem to find an option that sends me a positive DSN for delayed
mail, is there one? If not, is this something you'd consider implementing?

Thanks,
Florian

[Wietse Venema]

Post by Florian Pritz
I've currently set delay_warning_time = 4h and maximal_queue_lifetime =
5d, which are nice values and all, but if I get a delay DSN I'd like to
know sooner than after 5 days if the mail went through.

By default, Postfix requests a DSN for delayed and failed mail.

To request a DSN when mail is DELIVERED:

UNIX command line:

sendmail -N 'delay,failure,success'

SMTP protocol:

RCPT TO:<address> NOTIFY=DELAY,FAILURE,SUCCESS

After doing the above, you can trigger "success" notification when
mail leaves your network:

/etc/postfix/main.cf:
smtp_discard_ehlo_keywords = dsn

If you read this far, then you will inderstand that there will be
no separate option to request a DSN when mail leaves your network,
because the above features already provide this function.

References:
http://www.postfix.org/DSN_README.html
RFC 3461 (SMTP DSN Extension)
RFC 3462 (Delivery Status Notifications)
RFC 6533 (Internationalized Delivery Status Notifications)

Wietse

[Florian Pritz]

Post by Wietse Venema

Post by Florian Pritz
I've currently set delay_warning_time = 4h and maximal_queue_lifetime =
5d, which are nice values and all, but if I get a delay DSN I'd like to
know sooner than after 5 days if the mail went through.

If you read this far, then you will inderstand that there will be
no separate option to request a DSN when mail leaves your network,
because the above features already provide this function.

Thanks for the explanation, but I already know you can request a success
DSN when sending email. My questions is different in that I only want a
success DSN if the mail has previously generated a delay DSN and I don't
want success DSNs all the time. Basically I want a "your mail is no
longer being delayed and has been delivered to the next hop" DSN.

This doesn't seem to be covered by the RFCs so I understand if this is
not possible, although I'd consider it a useful feature.

[Wietse Venema]

Post by Florian Pritz

Post by Wietse Venema

Post by Florian Pritz
I've currently set delay_warning_time = 4h and maximal_queue_lifetime =
5d, which are nice values and all, but if I get a delay DSN I'd like to
know sooner than after 5 days if the mail went through.

If you read this far, then you will inderstand that there will be
no separate option to request a DSN when mail leaves your network,
because the above features already provide this function.

Thanks for the explanation, but I already know you can request a success
DSN when sending email. My questions is different in that I only want a

I can assure you that I have no difficulties comprehending this
difference, so there is no need to repeat your explanation.

Wietse

[LuKreme]

Post by Florian Pritz
Thanks for the explanation, but I already know you can request a success
DSN when sending email. My questions is different in that I only want a
success DSN if the mail has previously generated a delay DSN and I don't
want success DSNs all the time. Basically I want a "your mail is no
longer being delayed and has been delivered to the next hop" DSN.

Should be something that you can do yourself. Keep a table of the messages that have generated a delay DSN, check success DNS messages against it, and chuck out the ones that don’t match.

Also, assuming you get time stamps in the DSNs, you could pre-filter by chucking out anything that is less than a minute/hour/day old, as suits your needs.

[Wietse Venema]

Post by Florian Pritz
Hi,
I've currently set delay_warning_time = 4h and maximal_queue_lifetime =
5d, which are nice values and all, but if I get a delay DSN I'd like to
know sooner than after 5 days if the mail went through.
I can't seem to find an option that sends me a positive DSN for delayed
mail, is there one? If not, is this something you'd consider implementing?

I think that this can be implemented without a significant amount
of code. Thus, it is likely to work correctly.

First, when the queue manager selects a message for delivery, it
needs to find out that a "delayed" DSN was sent for that message.
That is easy. Each Postfix queue file either contains no delay
warning record, or it contains a delay warning record with a time
value that says when to send a "delayed" warning. A zero time value
means that the "delayed" warning was already sent.

Once the queue manager sees that the "delayed" DSN was already sent,
it sets a new NOTIFY flag for all subsequent delivery attempts.
That new flag is almost like the standard NOTIFY=SUCCESS flag,
except that this flag is not sent to a remote SMTP server. Instead,
the Postfix SMTP client reports a "relayed" status. Other Postfix
delivery agents will treat this new flag as the standard NOTIFY=SUCCESS
flag, and report a "delivered" status.

Wietse