Anti Spam Scores
With firmware 49.5 the process of fine tuning the Anti Spam Scores has reached a new level. It is now possible to edit the score of any Anti Spam rule, in addition to those that were already customizable up to the previous firmware.
The configuration page is available through menu Anti Spam > Advanced Configuration > Anti Spam Scores.
Here the page shows a list of pre-existing Anti Spam rules that are also customizable through an advanced setup page in menu Anti Spam > Setup.
In addition to the existing ones, it’s possible to add other rules and assign them a custom score, which will override the default one. The Rule Names must be valid Spamassassin rules, otherwise they will be ignored.
When a rule is not in this list or when it’s deleted from the list, the Protector will use the default score.
To add a Spamassassin rule, enter its name in the Rule Name field, then type the custom score and press . To alter the score of a rule in the list, it’s enough to click on the rule name and enter the new score in the edit page.
Valid scores are positive or negative floating point values. Please remember that a positive score will increase the chance that a mail message is considered spam, a negative score will increase the chance that a mail message is considered clean.
Here are the pre-existing rules, with a correspondence on the Anti Spam Setup page:
BOUNCE_MESSAGE and ANY_BOUNCE_MESSAGE, that fire when the NDR Protection is active;
RDNS_NONE, associated to the reverse DNS lookup check.
RP_MATCHES_RCVD, which is associated to the Envelope Sender override option. As this is an overriding rule, it must nullify the default score; in this case any change to the predefined score should be zero or a negative value.
SPF_PASS, SPF_FAIL and SPF_HELO_FAIL, that fire when the SPF Record options are enabled.
The rules that the Anti Spam filter fires on messages, are visible in the Mail Archiver > Message Listing, clicking in the space between [ ]. In this page, the rules are listed in the Spam Report section.
This page is for advanced users only. The default scores are valid in almost every case and should be altered only in exceptional cases. Assigning a non-default score can alter the Anti Spam filter in a way that might make it ineffective.
Weak Ciphers: The Protector system has been prepared for the removal of weak ciphers from the Mail Transfer Agent, when the TLS option is enabled and mail is transferred through port 465. In the next firmware the transition will be completed and it will be possible to disable weak ciphers without affecting the mail transfer.