[vox-tech] postfix question: content inspection for junk elimination

[Rod Roark]

On Wednesday 30 June 2004 10:44 am, Henry House wrote:
> På onsdag, 30 juni 2004, skrev Rod Roark:
> [...]
> > Also, starting with release 2.1, Postfix has a little-known
> > feature that will allow content filters to reject mail
> > BEFORE the offending SMTP connection is closed.  I went out
> > of my way to install 2.1.1 along with my recent server
> > upgrade, intending to try this out soon.  See:
> > 
> >   http://www.postfix.org/SMTPD_PROXY_README.html
> 
> 
> Nice. This is exactly what I am looking for, though it is worrysome that the
> documentation says that external content filters are only suitable for
> low-traffic sites. Rod: have you experimented with this yet? Has anyone
> else?

Not yet, unfortunately.  Obviously the definition of "low
traffic" is nebulous, and will also depend on the specific
content filter chosen and its configuration.  For you and me
I'm pretty sure it's a non-issue.
 
> Honestly, I think the e-mail system is going to become unusable in the
> not-too-distant future and we will all be forced by circumstances to switch
> to a sender-pays-per-message system. Think how much less profitable
> indiscriminate bulk mailing would be if the sender had to pay you one cent
> for every message successfully delivered!

I don't think that will happen.  Spam filtering is very
effective if done right.  Currently I filter almost
exclusively based on RBLs and custom IP blocking (not
message content, other than viruses), and that catches
about 99% of the junk.

I suppose I'll do content filtering when the need increases
to 99.9+%.  As spam escalates, so will the measures that are
taken against it.

-- Rod