
50CHAPTER 4: ANTI-SPAM CONFIGURATION
■Redirect to: The message will be delivered to the mail address specified in Action Data.
■Reject mail: The mail will not be accepted and the connecting mail server is forced to return it.
■BCC (Blind Carbon Copy): The message will be copied to the mail address specified in Action Data.
■Action data — Depending on the specified action:
■Modify Subject Header: The specified text will be inserted into the subject line, such as [BULK].
■Add header: A message header will be added with the specified text, such as [BULK].
■Redirect to: Send the message to a mailbox such as spam@example.com.
STA | STA (Statistical Token Analysis) is a sophisticated method of identifying |
| spam based on statistical analysis of mail content. Simple text matches |
| can lead to false positives because a word or phrase can have many |
| meanings depending on the context. STA provides a way to accurately |
| measure how likely any particular message is to be spam without having |
| to specify every word and phrase. |
| STA achieves this by deriving a measure of a word or phrase contributing |
| to the likelihood of a message being spam. This is based on the relative |
| frequency of words and phrases in a large number of spam messages. |
| From this analysis, it creates a table of “discriminators” (words associated |
| with spam) and associated measures of how likely a message is spam. |
| When a new incoming message is received, STA analyzes the message, |
| extracts the discriminators (words and phrases), finds their measures from |
| the table, and aggregates these measures to produce a spam metric for |
| the message between 1 and 100. |
| STA uses three sources of data to build its |
| ■ The initial database tables based on analysis of known spam. |
| ■ Tables derived from an analysis of local legitimate mail. This is referred |
| to as “training.” |