I am running my own e-mail server. This also means, I have to fight spam by myself. I am using Spamassassin, like everybody else and it works fine most of the time. Recently, however, I have been getting quite a bit of spam that looks really sophisticated - it has SPF headers, proper formatting etc. One thing it has in common is, it's sent from the newly added top level domains, like .icu, .club, .xyz and the like. And we can use that.