Re: [tlug] state of the art spam filtering

[Curt Sampson <cjs@example.com>]

On 2010-03-16 13:58 +0100 (Tue), Francois Cartegnie wrote:

> * Reject senders with reverse DNS containing their IP (Catches 90% !)

I'm sure that's a fib, since you appear to get e-mail from me.

    $ host -t a beatific.cynic.net.
    beatific.cynic.net has address 203.141.153.20
    $ host 203.141.153.20
    20.153.141.203.in-addr.arpa domain name pointer 
	203.141.153.20.static.zoot.jp.

    $ host -t a dyadic.cynic.net.
    dyadic.cynic.net has address 122.103.239.152
    $ host 122.103.239.152
    152.239.103.122.in-addr.arpa domain name pointer 
	static-122-103-239-152.ng-fam.svips.gol.ne.jp.

Though it is true that you've never replied to any of they offers I've
made you for Viagra or extremely authentic-looking Rolex watches.

(For what it's worth, the first is a "business-ish" Interlink connection
with 8 IPs, about 12,000 yen per month including dedicated fibre
charges. The second is a GOL business connection, also with 8 IPs, for
about 23,000 yen per month, including dedicated fibre charges.)

> * Mails to non-exiting accounts goes to blackhole. Never bounce anything.

Ouch! There's the reason I don't get replies about the Viagra. I
mistyped your address when I was putting it into my address book, and I
never would have known about it had you not told me here.

But perhaps you could tell us a bit more about this, since it seems
a bit weird. I don't generate bounces for non-existent addreses: I
generate errors during the SMTP conversation. Rejecting the mail before
it's even sent to me seems cheaper than accepting it even if not to
generate a bounce.

cjs
-- 
Curt Sampson         <cjs@example.com>         +81 90 7737 2974
             http://www.starling-software.com
The power of accurate observation is commonly called cynicism
by those who have not got it.    --George Bernard Shaw