# Enable postscreen service

Attention

Check out the lightweight on-premises email archiving software developed by iRedMail team: Spider Email Archiver.

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:

    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 instead, it helps a lot too, but less effective than postscreen service.

## References

- Postfix Postscreen Howto
- Postfix manual page: postscreen(8)