Retarus Glossary

Email Security Report


The email has been quarantined because it contains a file attachment that is on a blacklist that applies to you.


The email was blocked because the sender's email address was on one of your blacklists.

CxO Fraud

The email is checked by Retarus CxO Fraud Detection and classified as suspicious or potentially fraudulent if the sender address is fake. For your protection, the email is moved to quarantine.


This email's DKIM (DomainKeys Identified Mail) signature is invalid. The sender could not be verified as the owner of the domain used to send the email, therefore the email was moved to quarantine.


The email was rated as a potentially unwanted newsletter and therefore moved to quarantine.

Message Size

The email was blocked due to Large E-Mail Handling. The message or the attachment exceeds the maximum permitted size.

NDR Spam

If there is an unusually high number of NDRs (Non Delivery Report, "Bounce" message), automatic protection mechanisms will take effect and this email will be blocked. This prevents the so-called "backscatter".


The email was moved to quarantine due to suspected phishing. You should not click on any links in the email.


The email's attachments undergo an in-depth analysis, and Retarus Sandboxing has delivered a suspicious result. For your protection, the email is moved to quarantine or deleted.


The SPF entry (Sender Policy Framework) of this email is invalid. The IP address of the sending MTA is not stored in the DNS entry. The email was therefore moved to quarantine or deleted.