450 4.3.2 - Postscreen

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450 4.3.2 - Postscreen

Maurizio Caloro-2

 

Hello

Today I have activate postscreen on mailserver, now one email will now reject but I understood that this

Will be delivered after some time….. “this are like in waiting”

 

Apr  7 18:49:36 ail postfix/postscreen[32484]: NOQUEUE: reject: RCPT from [40.92.73.101]:47169: 450 4.3.2 Service currently unavailable; from=[hidden email], to=[hidden email], proto=ESMTP, helo=<EUR04-HE1-obe.outbound.protection.outlook.com>

 

Please how long will this action take, or its possible to shorting this time?

 

Or I need to understood more about this postrscreen?

Thanks

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Re: 450 4.3.2 - Postscreen

Rob McGee
On 2021-04-07 11:57, Maurizio Caloro wrote:
> Today I have activate postscreen on mailserver, now one email will now
> reject but I understood that this
>
> Will be delivered after some timeā€¦.. "this are like in waiting"

Depends.  There are some transactional mail senders which do not
retry.

> Apr  7 18:49:36 ail postfix/postscreen[32484]: NOQUEUE: reject: RCPT
> from [40.92.73.101]:47169: 450 4.3.2 Service currently unavailable;
> from=[hidden email], to=[hidden email], proto=ESMTP,
> helo=<EUR04-HE1-obe.outbound.protection.outlook.com>

Microsoft's outbound server farm certainly WILL retry.  I do not
know, however, if they will retry from the same IP address.

> Please how long will this action take, or its possible to shorting
> this time?

That's entirely up to the sending client.  Most should retry in a
matter of minutes.

The delay can be avoided if the sending client is whitelisted, and
indeed all the Microsoft outbound farm hosts are listed in
list.dnswl.org's whitelist.

> Or I need to understood more about this postrscreen?

You definitely do.

You should not have enabled the after-220 tests before you
understand what they do and what they cost you.

http://www.postfix.org/POSTSCREEN_README.html is the primary
reference.

http://rob0.nodns4.us/postscreen.html is my own configuration.  It
includes an example of the aforementioned whitelist feature
(
http://www.postfix.org/postconf.5.html#postscreen_dnsbl_whitelist_threshold 
).
--
   http://rob0.nodns4.us/