Matus UHLAR - fantomas:
If filter was able to strip NOTIFY=, we'd have fine control over when to
send notifications...
On 31.07.17 07:14, Wietse Venema wrote:
There is an example that modifies DSN commands in
http://www.postfix.org/postconf.5.html#smtpd_command_filter
That means we could use smtpd_command_filter to replace NOTIFY=(.*) by
NOTIFY=NONE if smtp/milter header contains e.g. "X-Spam-Flag: Yes,"
possibly doable, although I currently can't imagine, how.
On 31.07.17 09:16, Tomas Macek wrote:
2) how much is it normal to turn off the DSN for outside world?
I guess that while this is not very common, but with this king of spam
spreading it may get applied on more servers, thus effectively lowering
usefullness of DSN extenaion.
That's also why I search for better solutions...
On Mon, 31 Jul 2017, Matus UHLAR - fantomas wrote:
I am trying to prevent notifications to messages considered spam but that
needs support from spam filter. You can send NOTIFY= to filter over LMTP,
where filter would pass it back to postfix (over LMTP again).
If filter was able to strip NOTIFY=, we'd have fine control over when to
send notifications...
1. I don't know how effective would this be. Maybe we'd need to disable
notifies at all.
2. seems that postfix 2.9 doesn't send NOTIFY=SUCCESS to LMTP filter, but
sends notify imediately. 2.11 does not have this problem.
see http://marc.info/?l=postfix-users&m=150107262526121&w=2
On 31.07.17 14:54, Tomas Macek wrote:
And what about to use a before-queue Milter? May it be helpful?
I like before-queue filters (and milters) because they prevent spam from
being received and handled, and in case of problems we have clean hands (the
mail was not accepted, it's up to the sending MUA to handle the DSN).
on another (not-yet mentioned) machine, I use milter. Many of those
(NOTIFY=SUCCESS) spams got rejected. Still, some DSNs were generated.
So I still serch for solution (if there's any).
looking at milter API, seems that milter could replace recipients got by
xxfi_envrcpt by calling smfi_delrcpt and smfi_addrcpt_par...
According to doc
http://www.postfix.org/MILTER_README.html#limitations there is
supposed to be a limitation if we use before-queue filters only and I
don't have any.
The doc says:
---
When you use the before-queue content filter for incoming SMTP mail
(see SMTPD_PROXY_README), Milter applications have access only to the
SMTP command information; they have no access to the message header
or body, and cannot make modifications to the message or to the
envelope.
---
Is Milter able in that case modify headers?
"modify headers" is subset of "motifications to the message", thus the
answer is NO.
However, this only happens when someone has both smtp proxy (before-queue
filter) AND the milter, which I don't think happens at all.
You don't have smtp proxy, so why care?
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
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