Is there a way to configure the "IP Block List Providers" filter in MS Exchange 2010 to put the identified spam message into user's Junk Email folder rather than blocking it completely?
Some of the mail is being incorrectly blocked by the DNSBLs, and it'd be great if the user could review the messages himself.
Thank you.
Unfortunately, this is not possible. The IP Block List Providers filter is a Connection Filtering filter, and these will either reject and stop processing messages or accept and pass them along to the next one. For these filters, there's no option to set Spam Confidence Levels (SCL) that could be used later on to flag messages as spam and put them in the junk mail folder.
If your DNSBLs cause you to reject mail from legitimate senders too often, you might want to switch blocklist providers, and if it's always the same sender being blocked, you could add his mail server's IP to the allow list. Since the IP Allow List filter, by default, has a higher precedence than either of the block list checking filters, messages from IPs on the allow list will be exempt from further connection filtering checks.
(Source and more information: Understanding Anti-Spam and Antivirus Mail Flow)
