You can create a blacklist in the badmailfrom configuration file. A blacklist specifies SMTP clients that are prohibited from using your mail server to send email. For example, you can prohibit an SMTP client from sending junk mail through your mail server by specifying an email address, such as frankj@mydomain.com, in the badmailfrom configuration file. You can also block an entire domain from sending email through your mail server. In the following example, two items are added to the badmailfrom configuration file. The first is a domain name, and the second is an email address.
To create a blacklist
1. Click Application Starter, Utilities, Text Editor.
2.Type the following into the Text Editor:
mydomain.com
frankj@myaddress.com
3. Save the file as /var/qmail/control/badmailfrom.
Note
It is important that your save this file as badmailfrom. Do not include a file extension. If you do, the mail server might not read the file.