Sendmail: How does one blacklist annoying spammers?

[Tom Horsley]

On Fri, 25 Jun 2010 14:54:27 -0700
JD wrote:

> I wonder how Google does it. only .01% of my google email is spam.
> The spam folder contains tons of spam, and it is automatically purged
> by google.

Yea, I just use gmail as my mail provider and download the
mail with fetchmail. I think one non-spam item wound up
in my gmail spam folder in several months.