Plusnet hosted email - spam bouncebacks

There are multiple levels of filtering, each an external service that plusnet pays handsomely for.

The first level is before the whitelist, and bounces back to the sender all emails from IP addresses that are known to be used by spammers. SS have confirmed they are receiving bounceback from plusnet against my email address with "spam" as the reason. This reduces the processing load considerably, and protects the plusnet infrastructure from the almost denial of service level of spamming that happens occaisonally (as per overnight 13th/14th Nov). The downside is I can't receive any email from organisations that use email hosting companies (such as Amazon Web Services) that are perpetually flagged as being used by spammers.

If an email passes that first test at plusnet, the whitelist is processed [EDIT: not just yet]. If it is on the whitelist it heads straight to the inbox. Otherwise further checks are done, some as part of the standard plusnet email package, others are paid for extra subscription checks. There is also a configurable option as to how agressive you want the spam filter to be, I have it set at the lowest. These checks assess the probability of a given email being spam, and route to various configurable spam folders (depending on the extra subscription(s) paid for). By cross checking with multiple spam filters, the problem RR referred to of good emails being falsely marked as spam is diminished, and anything that does end up in my spam folder is almost certainly spam.

Only the first check bounces emails back to sender, all subsequent checks will deliver the email to a folder somewhere. [EDIT: not so]

Discard Obvious Spam

This is an extra layer of filtering. If switched on, emails with a spam rating above a certain threshold will be deleted. This is not the same as rejecting an email - the message will not be bounced back to the sender.

The threshold is set at a high level so only obvious spam should be deleted. If you suspect that legitimate email is being deleted by our anti-spam filters, then you should either switch this option off or add the address of the sender to your 'approved senders' list.