Glossary

Quarantined email

Quarantined email

A quarantined email is a message that has been flagged by an email security system (often a Secure Email Gateway (SEG) or an ISP) as suspicious but not definitively malicious. Instead of sending the email to the inbox or junk folder, it’s placed in a quarantine area where the recipient (or admin) can review and decide what to do with it.  

Emails might be quarantined due to:  

  • Failing authentication (e.g., SPF/DKIM/DMARC 
  • Suspicious attachments or links 
  • Content resembling phishing or spoofing attempts  
  • Anomalies in sender behavior or infrastructure  

Quarantining is a middle-ground decision, equivalent to “We’re not sure this is safe, but we’re not deleting it either.” Depending on the email client or security platform, users may receive daily quarantine digests, or have to check a separate portal to release or report messages. 

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