Which routing detail in an email can be useful for spam detection?

Building features from email headers to infer which relays handled a message is a possible direction for an anti-spam project.

A spam detector may inspect the email _____ to see which mail servers handled the message before delivery.

Match each email feature to its role in spam detection.

Arrange the steps for using message-routing information to improve a spam filter.

Which kind of signal is used by an email envelope/header based spam filter?

For an email filter system, only the message header and routing information should be used as the anti-spam approach.

Email headers can reveal the servers a message passed through

Match each message filter feature source to the kind of information it records.

Order the reasoning steps a team follows when deciding whether message-routing features are worth exploring for spam detection.

Using Message Routing Data to Identify Unwanted Mail

Using Message Routing Metadata to Improve Spam Detection

Routing Information from Mail Headers