# Enable postscreen service

WARNING: With postscreen service enabled, your users must use port 587 to send email, port 25 will be used by postscreen service instead of normal smtp service.

## Enable postscreen service

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

1. Download script `enable_postscreen.sh` from iRedMail source code repository
2. Upload this script to your iRedMail server, then execute it to enable postscreen service:

    # 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.

## 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)