[nycbug-talk] greylisting (was OT: Spam Filters)

[N.J. Thomas]

* N.J. Thomas <thomas at zaph.org> [2008-10-23 14:24:14+0000]:
> Most sysadmins I know that use Postfix as their MTA say that
> greylisting (IIRC they mostly all use postgrey) cuts something like
> 60-95% of the spam they get

This reminds me of when greylisting first came out (ca. 2003 I believe),
a lot of people -- myself included -- figured that spammers would adapt
to it fairly quickly.

I figured we had about a year or two before spammers would just rewrite
their software to handle it. I'm *really* surprised to see this
spam-reduction technique still catching as much as it does today.

Wonder why this is.

My theory (that I can't back up in any way) is that either the people
sending the spam haven't updated their spam-mailing software to the
latest version or that spammers don't want to waste their time with the
small percentage of people who greylist when a larger share of folks
don't use it.

Thomas