Re: [Asrg] Re: [1] Why SPAM is worse in SMTP than in other protocols

[Tony Toews <ttoews@mvps.org>]

At 08:18 PM 2003/12/22 -0500, you wrote:

>   The LMAP discussion document (based on Hadmut's comments in RMX),
> says that the single hop use of SMTP is a large part of the reason why
> spam is so wide-spread.  There are 100's of millions of senders, each
> sending to only 100's of thousands of recipient MTA's.
>
> > How is this behavior helpful to stopping spam?
>
>   If that imbalance in the network was addressed, spam would become
> significantly more manageable.  It wouldn't stop entirely, but having
> a blacklist of 100K MTA's is signficantly easier than having
> blacklists of millions of IP's.
I have no particular expertise in mail servers or the Internet RFCs.  My 
viewpoint is thus quite simplistic.

I agree completely that the RFCs have to be changed, or some other 
mechanism, so that MTAs only take in email from other MTAs or authenticated 
clients of the MTA.   Recipient MTAs only accept emails from MTAs in the 
name lookup portion of the DNS.    Then we need some mechanism of ensuring 
that the recipient MTA is really receiving the email from the originating 
MTA.

From my very simplistic view of the email systems it seems to me that the 
msgid id could be part of the verification mechanism.   The originating MTA 
stamps the outgoing email with a unique message id.  Once the header 
portion of the email is received then the recipient MTA does a name lookup 
on the originating MTA and verifies that the originating MTA sent that 
msgid.  Once the receipient MTA finishes accepting the email the 
originating MTA then never uses that msgid again.

And if all of this means updating the worlds email servers over the next 
year or two, well tough.  I for one am getting real tired of getting a 
hundred bounces a day from spammers forging email address for my domains 
and 200 or 300 Swen virusses a day.  And my domains and I are an 
insignificant portion or the worlds email traffic.

Tony
-----
Tony Toews, Microsoft Access MVP
Microsoft Access Links, Hints, Tips & Accounting Systems at
   http://www.granite.ab.ca/accsmstr.htm