For some reason over the last few weeks we have been flooded with spam that all originates from the extension .Biz ... It is very annoying and has now drawn the ire of my CEO who manages to get several hundred a day. Even though it is unconventional, is it possible to block or reject all email that comes with the extension .biz for example email@example.com or firstname.lastname@example.org? Most of the email domains are masqerading as common and popular email domains except for the 'biz' part.
Any suggestions would be great
PS: I am also open alternative methods that may work. I am not locked into any specific solution.