Administrator's Guide - Kerio Software Archive

16.6 Spam repellentFigure 16.9SPFOnly log this to the security logMessages with an invalid SPF record will be only added to the Security log.Block the messageMessage including invalid SPF will be blocked on SMTP level. Senders are informed thattheir message cannot be delivered.Add this value to the message’s spam scoreThe value set here will be added to message’s total score (see section 16.1).In case of the SPF method, it is recommended to use value from 1 to 3 points.Don’t check SPF from this IP address groupUse this option especially for specifying backup servers. If a message is sent througha backup server, the IP address of the server does not match the ones allowed for thedomain. Therefore the messages from these addresses should not be checked.Warning: To ensure a full functionality of SPF, do not add any other servers than thebackup servers to this group.Note: Details about the SPF check are displayed in the Debug log, after the appropriate settingsare specified (for more information, see chapter 22.8).16.6 Spam repellentKerio MailServer is able to check the delay of reply to SMTP greeting.Kerio MailServer requests communication according to RFC (see glossary) which defines SMTPtraffic. Most of the spam distributing applications do not follow RFC. Thus, Kerio MailServeris able to distinguish them from legitimate SMTP servers.187