Re: [tlug] state of the art spam filtering

[Christian Horn <chorn@example.com>]

On Tue, Mar 16, 2010 at 09:25:24AM +0100, Attila Kinali wrote:
> 
> I'd like to take on Josh's proposition to talk about
> spam filtering. Especialy about current, non-intrusive
> methods available.
> 
> My current setup for the high-volume domains
> is to have strict envelope-from/envelope-to checking
> on both primary and secondary MX and reject everything
> with a 4xx that has an invalid envelope-from, resp 5xx
> if the envelope-to is invalid. 

I use greylisting for my own lowvolume domain, from remembering 
the situation bevore (so no real numbers) its working nice.
The initial delay for mails from yet unknown domains is un-
pleasant thou.

The idea of blacklists seems a bit scary since it could enable
others to censor your mails.  Ofcourse information from usual
DNS that is used to count signs of spam cannot be trusted either
but blacklists are different.

Tarpit was mentioned recently.

Another interesting idea seems to be mxallowd, its refusing to
accept mail on the first mx-host and just if another delivery
is attempted to an alternative mx-host the mail is accepted.
I currently just use this single server setup with only one
ipv4-ip thou cannot use this.


Christian