How to configure SpamAssassin on a Plesk server?

Settings will be applied server-wide.

• The maximum number of worker spamd processes to run
  Set the maximum number of worker spamd processes to run. By default, the maximum number of SpamAssassin processes which could be configured via the Plesk GUI is 32. If it is required to run more SpamAssassin processes simultaneously, add the following lines to the panel.ini file:

  [mail]
  spamAssassin.maxChildrenLimit = 80

• The score that a message must receive to qualify as spam
  A message is considered to be a source of spam if the number of hits exceeds the established threshold. By default, the filter sensitivity is set so that all messages that score 7 or more points are classified as spam.
  If users still receive spam messages with the default score, to increase sensitivity, set a less value, for example, 6.
  If SpamAssassin marks valid messages as spam, decrease the sensitivity by setting a higher value, for example, 8.

• Add the following text to the beginning of subject of each message recognized as spam
  Specify how to mark messages recognized as spam. Leave this field blank if it is not required to add any text. Type _SCORE_ if it is required to include the score in the message subject:
  

Options available only on a Plesk for Windows Server:

• Do not filter if mail size exceeds specified size
  Define the maximum size of messages in kilobytes(KBytes) that SpamAssassin will process.

• Trusted languages
  Specify trusted languages using the lists. Email messages that use the specified language will always pass the filter.

• Trusted locales
  Specify trusted locales using the lists. Email messages that use the specified locale groups will always pass the filter.

SpamAssassin settings can be adjusted individually for each mailbox in Domains > example.com > Mail Accounts > john.doe@example.com > Spam Filter tab.

• Switch on spam filtering for this email address
  Turn on/off SpamAssassin spam filter for the particular mailbox.

• What to do with messages classified as spam
  Allows to select one of three available options:

  
  

• Filter sensitivity
  A message is considered to be a source of spam if the number of hits exceeds the established threshold. By default, the filter sensitivity is set so that all messages that score 7 or more points are classified as spam.
  If users still receive spam messages with the default score, to increase sensitivity, set a less value, for example, 6.
  If SpamAssassin marks valid messages as spam, decrease the sensitivity by setting a higher value, for example, 8.

• White List
  Email messages coming from senders in the white list are not checked by the spam filter.

• Black List
  Email messages coming from senders in the black list are blocked.

Options available only on a Plesk for Windows Server:

• Trusted…