How can I set up my own RPTU SPAM filter?

The RHRZ operates a central SPAM filter.
This evaluates incoming e-mails based on many different criteria. The sum of all individual evaluations determines the classification of an e-mail as:

a) almost certainly SPAM,
b) possibly SPAM,
c) probably not SPAM.

a)
E-mails that are almost certainly SPAM are not accepted. In this case, the sender of the e-mail will receive a notification. Every accepted e-mail is also delivered to the user. In no case an e-mail will be discarded by the filter.

b)
E-mails that are possibly SPAM are marked (entry in the mail header) and are also forwarded to the user's mailbox. This marking can be evaluated by own rules if necessary, in order to sort out also such e-mails automatically:
  • It must be avoided that regular e-mails are rejected by mistake. Therefore, e-mails are delivered to the user "in case of doubt".
  • For e-mails that are considered to be possibly SPAM, the key "X-Spam-Score:" is added to the e-mail header, among others, e.g. "X-Spam-Score: *** (3.031)" The number in brackets is the spam score of the email. The larger the value, the more likely it is SPAM. The number of `*` corresponds to the integer part of the spam score.
It is possible to create your own stricter SPAM filter by moving emails above a certain SPAM score to the Spam/Junk folder by rule. The rule would check if the header contains the text
X-Spam-Score: ***
occurs in the header and move such e-mails. With the number of `*` the "sharpness" of the SPAM filter can be set: the less `*` the earlier the filter takes effect. (Currently there can be a maximum of four `*`, e-mails with even worse ratings will not be accepted).


c)
Emails that are probably not SPAM will be forwarded to the user's mailbox.



Important notes on creating such a rule:
  • Anyone using this should be sure to check the Spam/Junk folders regularly to avoid missing any regular emails!
  • The rule should run on the mail server (Communigate or Exchange) and not in the respective mail client.
  • RHRZ cannot provide support for creating email rules or even for troubleshooting due to own rule.