I think you would have to run your own email server for that (but you will likely not have the same uptime as a cloud provider, resulting in lost messages anywa

I think you would have to run your own email server for that (but you will likely not have the same uptime as a cloud provider, resulting in lost messages anyway). All of the cloud providers have to filter spam as a selling point to their users, and at scale they have to blackhole them for efficiency (pipe to /dev/null instead of storing the same viagra email for millions of users). Also for security if they detect a known virus they may want to delete it rather than let users risk spreading it.