MIS uses both third party Spam blocklists (also known as "RBL"s, or Realtime Block Lists), as well as private Spam filters that are set up on a case-by-case basis.
If you'd like to check and see if a mail server or ISP is on one of the third-party Spam blocklists we subscribe to, enter the domain name (i.e. the part after the "@" symbol in an email address, such as "hotmail.com", "freestuff.com", etc) in the box below and click "Submit":