Check if header has a valid id:
< id-left @ id-right >

clamav (Clam Anti Virus) checks incoming (and outgoing) emails on „malware“, virus pattern will be updated every hour.

Infected emails will be rejected with error code at SMTP-layer.

Attachements with extensions bat|cmd|com|dll|exe|inf|js|jse|pif|reg|scr|vb|vbe|vbs|wsf|wsh will be deleted,
recipient and sender will be informed.

All emails, that passed the former tests will be delivered, even if SpamAssassin rates the email as spam.

Starting with spam score 3.5 "[ SPAM? ]" will be added to the subject.