>Biggest problem is, that Microsoft always blacklists the whole server! If only one of my customers does something not in line with the secret rules of SmartScr

>Biggest problem is, that Microsoft always blacklists the whole server! If only one of my customers does something not in line with the secret rules of SmartScreen, emails of all other customers are blocked too. IMHO this is just unprofessional. Why not just block the domain under suspicion and send the adminstrator a message (maybe as part of the JMRP)? The reason for blocking IP originates from a culture set before DKIM. Any IP could shoot out emails for any domain. You don't want to blacklist a domain for an email it did not legitimately author. However, in a post DKIM world, where adoption is above 80% this could be a feasible solution at least for emails carrying a DKIM signature. The domain owner has provided proofs that the IP address is being used by them to send out emails. Flagging emails from a domain and IP could be blocked while allowing other domains from the same IP to operate.