BCP38 thread 93,871,738,435 + SPF

Douglas Otis dotis at mail-abuse.org
Fri Oct 27 22:33:59 UTC 2006

On Oct 27, 2006, at 10:03 AM, Chris L. Morrow wrote:

> On Fri, 27 Oct 2006 Michael.Dillon at btradianz.com wrote:
>> Or you could look at it as a weakness of SPF that should be used  
>> as a justification for discouraging its use. After all if we  
>> discourage botnets because they are DDoS enablers, shouldn't we  
>> discourage other DDoS enablers like SPF?
> under this assumption we should discourage user use of the  
> internet... :(
> anyway, please let's get back to the original discussion :)

As Steve already pointed out, BCP38 is not a complete solution.  Not  
only does SPF prevent the source of a Botnet attack from being  
detected, it also enables significantly greater amplification than  
might be achieved with a spoofed source DNS reflective attack.  In  
addition, the Botnet resources are not wasted, as their spam is still  
being delivered.  This aspect alone dangerously changes the costs  
related to such attacks.   It seems wholly imprudent not to consider  
SPF in the same discussion.


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