Published February 12th, 2004 by Jim O'Halloran
Greylisting for Spam Control?
This paper outlines a new method for spam control which the authors have called Greylisting. I haven’t read the whole thing yet, but it looks interesting.
Greylisting has been designed from the start to satisfy certain criteria:
1. Have minimal impact on users
2. Limit spammers ability to circumvent the blocking
3. Require minimal maintenance at both the user and administrator level
Greylisting could be a good way of bridging the gap until SPF can be widely implemented. I still beleive SPF is a good long term result because it makes the forgery of From addresses extremely difficult, hence forcing spammers to use fixed IPs and domains which can be easily filtered.