I admin this website for 3 years already and despite it being just a small obscure card game - there haven't been a month without a challenge, where I had to go and change something manually.
This postfix workaround is pretty perfect for now, I enjoy looking at maillog right now and see the Nov 22 12:46:24 www postfix/cleanup[6977]: 7D4218048A0: discard: header To: pre.a.c.hfc...@gmail.com from local; from=<webmas...@xxx.de> Nov 22 12:46:27 www postfix/pickup[6966]: E59B88048A0: uid=48 from=<webmas...@xxx.de> Nov 22 12:46:27 www postfix/cleanup[6977]: E59B88048A0: discard: header To: fu.t.i.li.t.y.g.i....@gmail.com from local; from=<webmas...@xxx.de> Nov 22 12:46:30 www postfix/pickup[6966]: 266D88048A5: uid=48 from=<webmas...@xxx.de> flying through (every 3 seconds!) and those bastard messages being discarded. If you think, that a CAPTCHA or anything else will stop all the problems and you never have to touch anything, you are so wrong :-)