We generally recommend that you regularly review your Spam folder to check for any legitimate messages, and report them to the spam filter as “Not spam”. This keeps your spam filter tuned to new types of incoming spam while not becoming overly effective.
It might become tedious to sort through all the messages in your Spam folder to find possible false positives (legitimate, misclassified messages), and the following explains how to avoid sorting through the messages most likely to be spam.
How the Runbox spam filter works
The internal Runbox spam filter actually consists of two separate anti-spam systems working together: SpamAssassin, a rule- and signature-based spam filter, and Dspam which is your own, trainable spam filter and personal spam token database.
The two spam systems work together to scan incoming messages and insert message header tags specifying whether or not they are considered to be spam. Before the messages are delivered to your account, the actual spam filter sorts messages tagged as “spam” to your Spam folder.
Setting up fine-grained spam filtering
Because most spam is caught by SpamAssassin and is very unlikely to be legitimate email, it is possible to set up a manual filter to separate the “SpamAssassin-spam” from the “Dspam-spam” and save the messages most likely to be spam to a separate folder. You can then largely ignore this folder and only scan your “Dspam” folder for possibly misclassified messages. To keep your trainable spam filter up-to-date it’s important that you consistently correct it whenever it makes a mistake.
To set up advanced spam filtering, follow this procedure. Note: Omit the quotes when typing in the input fields.
- In Webmail, create a folder called “Spam”, and another one called “Maybe-Spam”.
- In Manager:Filter, set your spam filter to save spam to folder “Maybe-Spam”.
- In Manager:Filter, create a manual filter with the following parameters:
Messages where: [Header] [contains] "X-Spam-Flag: YES" will be [saved to folder] "Spam".
The filter’s priority must be set to “-2” (minus two).
You can now quite safely ignore your “Spam” folder and only scan the “Maybe-Spam” folder for misclassified legitimate email.
Note that your spam filter should be mature before this is attempted, as internal training of the trainable spam filter is bypassed in the above setup. Also, messages caught by Dspam (not by SpamAssassin) will bypass your whitelist.
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