Forum Discussion
BCL Values
You could use the Mail traffic reports from the https://technet.microsoft.com/en-us/library/dn500744%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396#BKMK_Viewmailprotectionreportsintheoffice365admincenter or from powershell using the https://technet.microsoft.com/en-us/library/jj200682%28v=exchg.160%29.aspx?f=255&MSPPError=-2147217396 cmdlet
After updating the value, monitor if you are getting more or less or same amount of junk mail that is being received. You can evaluate over a couple of days to get a better picture.
How do you monitor? Is there a chart or graph somewhere?
You could use the Mail traffic reports from the https://technet.microsoft.com/en-us/library/dn500744%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396#BKMK_Viewmailprotectionreportsintheoffice365admincenter or from powershell using the https://technet.microsoft.com/en-us/library/jj200682%28v=exchg.160%29.aspx?f=255&MSPPError=-2147217396 cmdlet