Finally, I’ve had to enable greylisting for this domain due to ever increasing levels of spam. Fortunately, setting it up is very easy. For Gentoo and Postfix, here’s a nice walkthrough:
Let’s hope that this, in conjunction with other anti-spam measures, will do it for a while.
Non-spammers shouldn’t experience any problems due to this change, but if you do, please contact me using Skype (mettlerd), phone or SMS.