Creating content filters

This feature is available if you have purchased a corresponding licence.

Each Content filters consists of general configurations, conditions and the content filter actions to be performed. See Creating content filter actions.

NOTE: You must first configure the content filter actions which can then be used in multiple content filter entries.

Step 1: Configuring attachment handling and archive handling

  1. Go to Configuration > Content filter > Content filters and click Add.
  2. Assign a unique name for the content filter.
  3. (Optional) Set the maximum size for emails by ticking the check box and using the slider.

    NOTE: Emails whose size exceeds the maximum allowed size are rejected.

  4. (Optional) Specify the email size above which the attachments are moved to the Web Portal.
  5. Specify the nesting depth from which emails are rejected.
  6. Click Next.

NoSpamProxy supports Content Disarm and Reconstruction (CDR) for the following archive formats:

  • ZIP
  • RAR
  • TAR
  • 7ZIP
  • BZIP, also in combination with TAR
  • BZIP2, also in combination with TAR
  • GZIP, also in combination with TAR
  • LZIP, also in combination with TAR
  • XZ, also in combination with TAR

The PDF document generated by CDR contains a link pointing to the original document in the Web Portal. The CDR-capable formats are listed in the content filter action on the Content Disarm tab.


The first CDR-capable attachment from an archive is converted into a PDF document and attached to the email. The remaining files remain in the archive and are uploaded to the Web Portal, if configured.

If you have selected the option Discard the original document, the archive is discarded. The storage location of the original document can be configured in the content filter action.

Step 2: Creating content filter entries

  1. Under Content filter entries, click Add.
  2. Assign a unique name for the content filter entry.
  3. Under Condition, click Add.
  4. Configure the condition that must be met to trigger content filtering actions and click Save and close.

    NOTE: Details on the configuration options can be found under Defining conditions.

  5. Under Actions, select the content filter actions that are triggered based on the conditions.
  6. Click Save and close.

The content filter entry appears in the list of content filter entries. The entries are processed from top to bottom and can be re-sorted with the arrows on the left side of the list.

Why do I need to configure an action for outbound emails?

NoSpamProxy requires a marking as trustworthy by Level of Trust in order to apply the action for trusted emails. Since only trust points are built up by outbound emails, this marking is missing, so that outbound emails are regarded as untrustworthy.

Step 3: Assigning content filters

To apply a content filter, you must assign it under Partners or Corporate users.

NOTE: Settings on email addresses take precedence over settings on domains, and settings on domains take precedence over the default partner settings.

Activate or deactivate content filtering rule-based

To enable or disable content filtering for individual rules, proceed as follows:

  1. Do one of the following:
    • Open an existing rule.
    • Create a new rule by clicking Add under Configuration > Rules > Rules.
  2. Turn content filtering on or off under Content filtering.
  3. Close the rule or configure it as desired.


Content filters