Hi @Adam L ,
Yes, the X-MS-Exchange-Organization-PCL
header is added by Microsoft. It’s part of the antispam stamps applied by Exchange Server to messages as they pass through the antispam features.
The X-MS-Exchange-Organization-PCL
header, also known as the Phishing Confidence Level (PCL) stamp, indicates the likelihood that a message is a phishing message based on its content. The PCL stamp is applied when the message is processed by the Content Filter agent.
The PCL values are described as follows:
- 1 through 3 (Neutral): The message content isn’t likely to be phishing.
- 4 through 8 (Suspicious): The message content is likely to be phishing.
Outlook uses the PCL stamp to block the content of suspicious messages. So, it doesn’t need a specific feature or level, but rather it’s a part of the antispam measures implemented by Microsoft. It’s used to help protect users from potentially harmful phishing emails.
More information, see: https://learn.microsoft.com/en-us/exchange/antispam-and-antimalware/antispam-protection/antispam-stamps?view=exchserver-2019
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