Spam is an annoyance and there’s a multitude of ways to counteract it. However spammers also get smarter and try to bypass filters and stuff. In addition, ICANN has lately approved a great mean gTLDs (generic Top Level Domains), like .biz, .info etc. Some of those gTLDs are, in my opinion, exclusive used by spammers. Lately, I have gotten a lot of spam from the .xyz gTLD. So the question was, how to block email coming from such domains using that gTLD.
Read the original at Howtoforge Linux Howtos und Tutorials.