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:
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
