This week has mostly involved me getting my live mail filtering site up and running with a guineapig or two.
This uses a custom user interface to allow users to manage the filtering settings for an entire domain:
- spam filtering.
- virus scanning.
- sender/recipient whitelisting.
- DNS-based blacklists
In terms of implementation this is an SMTP proxy which is built upon the qpsmtpd framework. I've got both the user interface and a collection of plugins reading all data from an MySQL database.
The practical upshot is that if you use the service you'll get less spam, and anything that has been rejected will appear in an online browsable quarantine for a period of times allowing you to view mistakes/rejected mails.
Any mail you didn't want, providing you've got the spam-filtering plugin enabled for your domain, you may send back to be trained as spam.
It scales nicely, doesn't appear to have lost any mail ever in real-world testing, and could be useful.