Rules, filters and actions

  • To process emails, NoSpamProxy applies rules that you can configure individually. For each email, the individual filters of the applicable rule are executed.
  • Filters evaluate how strongly the email meets a certain filter criterion and award corresponding penalty and bonus points. The awarded points are weighted with the multiplier of the filters and then added to a total value. If this value exceeds the set Spam Confidence Level (SCL) of the rule, the email will be rejected. You can set the allowed SCL individually for each rule. See Configuring filters and Filters in NoSpamProxy.
  • Actions in NoSpamProxy are called up after the filters have determined whether the email is rejected or allowed to pass. Actions can, among other things, modify the emails, for example to add a footer or remove unwanted attachments. However, actions can also reject emails that would actually happen after they have been evaluated by the filters. This means that a virus scanner, for example, can still reject the email even though it has not been detected as spam. Actions are therefore higher-level settings with which filters can be overridden if necessary. To find out which actions are available and how they work exactly, see Actions available in NoSpamProxy.