What is a Cloudmark fingerprint and how does it work?

Cloudmark is a messaging security and anti-spam company owned by Proofpoint. Through their Global Threat Network and anti-spam technology, they analyze billions of emails daily to determine their threat level for their customers. Cloudmark is used by many mailbox providers to help combat spam and covers over 1.6 billion mailboxes.

What is a Cloudmark fingerprint?

When the Cloudmark anti-spam solution scans an email message, it places the result of that scan into the email header of that message for the mailbox provider to review. The result of that scan contains the fingerprints of that message. The fingerprints are unique identifiers of different parts of your email such as the header, subject line, body, or footer.

How does it work?

When an email message is sent to a mailbox provider that uses Cloudmark anti-spam solutions, the filter:

  • Scans the entire email, which includes the header, subject line, body, and footer
  • Creates new fingerprints of content, URLs, images, and code
  • Compares the new fingerprints to the existing fingerprints in the Cloudmark database
  • Scores the similarity of fingerprints to messages considered to be spam or not-spam
  • Classifies the new fingerprints either as spam or not-spam based on its similarity to other messages in the Cloudmark database - and based on data received through Cloudmark's Global Threat Network

All messages sent to mailbox providers using Cloudmark's anti-spam solutions are fingerprinted, but not all fingerprints are considered spammy.

If a message receives a spammy fingerprint, participating mailbox providers will use that as a factor in their filtering decisions. Usually, mailbox providers will place some of your email in the spam folder, or block your email completely depending on their individual filtering policies and other internal factors related to your sending reputation and sending history.

What causes fingerprints to be considered as legitimate or spammy?

Fingerprints are considered legitimate or spammy based on similarities to other messages in their database and also from data collected through Cloudmark's Global Threat Network. This may include data about:

  • Complaints
  • Spam trap hits
  • Direct input from the Cloudmark community who votes on the messages being spam or not spam

This data is associated to your content in Cloudmark's database. Generally, the more complaints, spam trap hits and spam votes from the Cloudmark community that your messages receive, the more your message will be perceived to be spam and given a spammy fingerprint.

Go here to learn how to identify a Cloudmark spammy fingerprint using Inbox Monitor.


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