Information
When sender reputation is enabled on a computer, sender reputation filters all messages from all Receive connectors on that computer. Only messages from external sources are filtered. External sources are defined as non-authenticated sources, which are considered anonymous Internet sources.
Rationale:
Spam consumes a large amount of network bandwidth and server capacity. In addition, it is often the source of malicious software.
Solution
To implement the recommended state, execute the following PowerShell cmdlet:
Set-SenderReputationConfig -SenderBlockingEnabled $true -OpenProxyDetectionEnabled $true