Why doesn't whitelist work?

[pengyou]

I have just implemented the use of the whitelist feature on my space. I have one email account that is a "closed" account, i.e. I only send emails to people in my address book. I have noticed that I still get some of these mysterious returned email messages, even bthough I have not sent any emails out, let alone to email addresses that are invalid - I have checked the first 10 or so and they were all some kind of garbage. What is happening? Is there some way to make the whitelist feature more useful?

[felgall]

About 99% of all bounced email that everyone gets are spam messages that have both the To and From email addresses filled out by the spammer. Where the email is unable to be delivered to the To address the spammer hopes that the domain for the To address is incorrectly set up to bounce undeliverable emails instead of blackholing them. That way their spam then gets a second chance at delivery to he From address. The only way to fix this for where you are the From address is to set up your spam filter to delete all bounce messages as they arrive.

[pengyou]

Thanks! but if all bounced messages are deleted will this also delete genuine bounced emails?

[felgall]

A properly configured server will not bounce any emails - any it can't deliver will be discarded rather than bounced so while you are throwing away 0.1% genuine bounce messages along with the spam there will also be several times that many undelivered messages that you will never get bounce messages for regardless of what you do.