This is a list of IP Addresses that do not conform to more commonly known threats, and is usually because of compromised servers, hosts, or open relays. However, since there is little accompanying data this list COULD have false-positives, and we suggest that it only is used if you support a more aggressive stance. It normally requires that the IP Address has been observed to been executing excessive delivery attempts. However, this can occasionally happen even from normal email servers, because of bounce attacks, compromised email accounts, or other issues. Use with Caution.