[Mimedefang] Checking for a valid sender

[Alan Madill]

> On Tue, 18 Nov 2003, Alan Madill wrote:
> 
> > A large percentage of spam has a fake from address.  Has anyone
> > tried using md_check_against_smtp_server to test the senders
> > address?
> 
> No, and don't you try it!  md_check_against_smtp_server is designed to
> check the validity of a _recipient_ address.  There is no practical way
> to verify the existence of a _sender_ address (other than very mild tests
> like ensuring the domain has a valid MX or A record.)

I've gone through the man pages and I know what it was intended to 
do.

The reason that we have a spam problem to begin with is the SMTP 
protocol wasn't designed to deal with it.  What is needed is a new 
protocol or an extension to SMTP that does...

Verify that the sender is real.  (there goes 90% of your spam).

Built in white/black-listing (content management on the remaining 
10%)

Encrypted transfers.

That is the short list.  I'm sure you can think of other extensions.
-- 
Alan Madill - Aspen House Systems
250 567-4200