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Topic: Graylist Host Not found

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):
- Deployed with iRedMail Easy or the downloadable installer?DL
- Linux/BSD distribution name and version: centos 8
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): mysql
- Web server (Apache or Nginx):nginx
- Manage mail accounts with iRedAdmin-Pro? PRO
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
See questions below:

Postfix (SMTP)
Intended policy rejection, please try again later

Sample error message in Postfix log file:

    Jul 24 06:43:08 mx0 postfix/smtpd[12719]: NOQUEUE: reject: RCPT from sender.com[xx.xx.xx.xx]: 451 4.7.1 recipient@my-domain.com: Recipient address rejected: Intentional policy rejection, please try again later; from=sender@sender-domain.com to=recipient@my-domain.com proto=SMTP helo=

This error is caused by greylisting service, sender server will retry to deliver the same email, and your server will accept it after few retries.

1- "few retries" how many? and where do I set how many?

2- It soft reject messages with 451.4.7.1 -- How do I set it to 550 rejection so the sender know and gets a message back on the spot that they have a mis-configured server?

2 (edited by GerryM 2021-05-04 05:18:14)

Re: Graylist Host Not found

Greylisting and how to configure in iRedMail is documented here: https://docs.iredmail.org/manage.iredapd.html, and the default is for the sending server to wait at least 15 minutes before retrying.
You can also go to http://greylisting.org/ for more information.

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Re: Graylist Host Not found

GerryM wrote:

Greylisting and how to configure in iRedMail is documented here: https://docs.iredmail.org/manage.iredapd.html, and the default is for the sending server to wait at least 15 minutes before retrying.
You can also go to http://greylisting.org/ for more information.

Thank you for the reply, unfortunately the links you posted does not shed any light or help answering my questions. perhaps you can be more specific.

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Re: Graylist Host Not found

I thought I answered your questions! https://docs.iredmail.org/manage.iredapd.html in the Greylisting General Settings https://docs.iredmail.org/manage.iredap … l-settings it shows where to modify the message.
Most spam-bots connect to your server, send spam and disconnect without ever retrying. With greylisting, when a server connects the first time with your server, the temporary error is sent and the server is expected to retry later. If the server reconnects and it has been longer than the default 15 minutes, the email is accepted. If it is sooner than the default, the temporary error is again given.
But if you are wanting to send a 550 error on the first connection- this is not graylisting. Why would you want to reject?