# Enable postscreen service

!!! attention

	 Check out the lightweight on-premises email archiving software developed by iRedMail team: [Spider Email Archiver](https://spiderd.io/).

[TOC]

__WARNING__: With postscreen service enabled, your users must use port 587
(TLS) or 465 (SSL) to send email, port 25 will be used by postscreen service
to accept emails sent from other mail servers (not submitted by end users).

## Enable postscreen service

iRedMail ships a script to enable postscreen. You can enable it with shell
commands below:

```shell
wget https://github.com/iredmail/iRedMail/raw/master/tools/enable_postscreen.sh
bash enable_postscreen.sh
```

That's all.

Important notes:

* It will backup `/etc/postfix/main.cf` and `/etc/postfix/master.cf` first,
  if postscreen doesn't work, you can restore these 2 files.
* It uses several DNSBL servers by default, you'd better open
  `/etc/postfix/main.cf` (Linux/OpenBSD) or `/usr/local/etc/postfix/main.cf`
  (FreeBSD) to check the DNSBL servers it enabled, you're free to remove some
  of them (or add new ones) if you want.

## Disable postscreen service

If your iRedMail already have postscreen service enabled, it's easy to disable
it by following steps below.

* Open file `/etc/postfix/master.cf`, find lines below (usually they're first
  few lines in this file):

```
#smtp      inet  n       -       -       -       -       smtpd
smtp      inet  n       -       -       -       1       postscreen
smtpd     pass  -       -       n       -       -       smtpd
```

* Uncomment first line, comment out the other 2 lines:

```
smtp      inet  n       -       -       -       -       smtpd
#smtp      inet  n       -       -       -       1       postscreen
#smtpd     pass  -       -       n       -       -       smtpd
```

* Now restart or reload Postfix service. That's it. No need to modify any
  setting in `/etc/postfix/main.cf`.

## See Also

If you don't want to use postscreen service, you can [enable DNSBL service](./enable.dnsbl.html)
instead, it helps a lot too, but less effective than postscreen service.

## References

* [Postfix Postscreen Howto](http://www.postfix.org/POSTSCREEN_README.html)
* [Postfix manual page: postscreen(8)](http://www.postfix.org/postscreen.8.html)
