31 Oct
2013
31 Oct
'13
6:49 p.m.
John Levine wrote:
Right. Spam filtering depends on heuristics. Mail from hosts without matching forward/reverse DNS is overwhelmingly bot spam, so checking for it is a very effective heuristic.
Leading digit is clearly in widespread use beyond 3com & 1and1. One of the most effective heuristics in my acl list is: \N^.*@\d{3,}\.(cn|com|net|org|us|asia) In the last few hours it has picked off multiple messages from each of these: Carol28@8447.com Jeff17@3550.com Ronald79@0785.com Kevin57@2691.com Deborah76@3585.com Kimberly34@5864.com Sarah94@0858.com zavfdv@131.com qgmklyysyn@163.com pjpeng@163.com fahuyrw@163.com Daniel57@4704.com Helen95@2620.com