I do not know. I also do not know why people persist in using the Blocked
Sender list to block spammers. Spammers forge email addresses, and use
discardable email address, or just plain make them up. I just watched a
spammer morph through three variations of an email address, which would have
required three separate Blocked Sender entries, in two days. If you had a
list of 10,000 blocked email addresses, 9,999 of them would never match a
spam because the spammer will have moved on to another email address.

They didn't get past the DNSBL's on my local email server, but I didn't
write the rule right in the POP3 distributing client, and they sneaked one
through an ISP account. I fixed the rule. Instead of "If header matches...",
I changed it to "If expression matches, "From: localpart*@hotmail.com*",
"delete".

Don't look for those rules in MSOE, they don't exist; I use Mercury Mail for
a server for my hobby domain and Pegasus Mail as the mail client. Richer
filtering rules.