spf-discuss
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Re: SPF will solve spam and punish spammers

2004-07-24 08:36:31
On Saturday 24 July 2004 16:52, John Keown wrote:

I agree thousand are running secure and compliant servers but millions are
not adhering to the standards. Just look at the list of known open relays
mail servers on the net in any major blacklist. These have been used by
spammers and yet they are still open relays.

Are these systems really open relays, or trojaned systems turned into a spam 
relay?

When I look at some major ISP's in the country where I live, in most cases the 
top 10 of IP's generating most traffic (according to 
http://www.senderbase.org/) are cable modems or dialup accounts. In many 
cases these systems crank out hundreds of thousands of messages each day. A 
lot can be said about the accuracy of SenderBase, but even if they are off by 
a factor of 100, that's still a huge amount of messages for a normal user. I 
just can't believe that all these systems are badly configured mailservers, 
although most of them are listed in 'list.dsbl.org'.

The real problem behind this is that many internet service providers don't 
even bother to filter anything. All ports are wide open to anywhere on the 
net. This could be solved quite easily by a default setting of port 25 closed 
in- and outbound (except for the ISPs mailservers) and opening them on demand 
(via a web page or whatever). Your average Joe User with no desire to operate 
a mailserver (if he knows what it is) should not have access to these ports 
and will not be harmed if you close them for him. This will fit the vast 
majority of users just fine (maybe 90% or more). It can be done right now, 
the technology is there but many ISPs are unwilling to do so.

With spam now accounting for 80% of all email traffic we are fast
approaching email as a useless communication system.

Full ack. Something must be done. But before stepping to such drastic actions 
as putting additional requirements on running a mailserver, I think that we 
should first crack down on systems unknowingly running open relays.

Best regards,
Arjen
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