How to block/filter a specific server?

Lately I've been getting a lot of spams from a specific server from "cloudapp.net", but all of the sender e-mails, subjects and body are all different each time, but the server is still the same.

Is there a way to block or filter all of the e-mails from this "cloudapp.net" server? Like I said, even the sender's e-mail change on each spam, so I can't make a spam filter for them.