Loosing spam fight

[Jim Pingle]

Roland Smith wrote:
> Most spammers do not bother to return if they get a resend request.
> That's the whole point of doing this. So practically it doesn't increase
> bandwidth consumption.

This conversation is getting rather OT for -stable, but I felt the need to
ask a question:

To defeat this, wouldn't a spammer just have to send out the same spam twice
in a row from the same machines, spaced apart by a little time?

Bonus for the spammer: accounts on servers without greylisting would get two
copies of the spam.

Greylisting is a decent idea, but it seems to me that it's just another tool
in the ongoing arms race against spammers. It may work for a while, but
eventually they'll catch on and it will only cause unnecessary delays for
legitimate mail.

Jim