Reject SMTP connection if MXRate probability is greater than or equal to: MXRate scores can be a criteria for rejecting messages upon the initial connection from a remote server. If you decide to reject messages based on the MXRate score they will be immediately disconnected and very little data will be exchanged. MXRate scores will vary from 50 to 100. Senders of score is less than 50 will not be recorded in the MXRate database. The higher the MXRate score, the greater the probability is that the message is spam. Most users are very pleased with the results when they set this option to around 90.
If connection needs rejection criteria perform the following action: This option allows you to perform various actions when the MXRate probability equals or exceeds your set score. You can select to do nothing at all, respond with a 421 temporary error (although this is highly not recommended), respond 550 permanent error (recommended), tarpit the sender and accept the message, or accept the message and delete it after the message has been received with no further processing.
Generate random bogus 550 error responses when "Return permanent error" is selected: Normally MXRate will return a URL directing the user to the MXRate website where they can report a false positive if they believe one has occurred. Some users would prefer not to give spammers a clue what antispam software they're using and would rather return an error that the spammer could never figure out. If you select this option any one of several hundred bogus error responses will be sent back to the sender if they are rejected because of their MXRate reputation score.
Always tarpit connection if MXRate probability is greater than or equal to: If a message passes the initial MXRate test and is not rejected, you can still add target penalties to the connection if the score is higher than a preset amount. We recommend a value of 50. Generally if any sender that has a MXRate reputation score of 50 or higher, we are able to make a reasonable assumption that they are involved in sending some volume of spam. Tarpitting them a few seconds may discourage them if they are indeed a spammer.
There are two other options in the response mode section that only apply if you are using the Alligate AntiSpam filtering plug-in. Please refer to the Alligate AntiSpam documentation for recommended usage.