~control/badmailfrom-unknown
From Qmail-LDAP Wiki
This file contains blocked addresses for server without a PTR RR.
Example:
@hotmail.com
Notes:
- Multiline.
- This is useful to stop some spammer that use fake hotmail or yahoo addresses but mail from home-pc without a PTR RR dns record.
- Syntax as in ~control/badmailfrom.
