Information
Sender filtering compares a list of blocked senders that's maintained by the Exchange administrator.
Note: For more information on how to create the list for blocked senders, please visit: Use the Exchange Management Shell to configure blocked senders and domains for sender filtering
Note #2: Sender filtering is enabled (by default) on a system performing the Edge Transport server role.
Rationale:
Spam consumes a large amount of network bandwidth and server capacity. In addition, it is often the source of malicious software.
Impact:
Some legitimate messages may be blocked.
Solution
To implement the recommended state, execute the following PowerShell cmdlet:
Set-SenderFilterConfig -Enabled $true
Default Value:
True