[Asrg] where the message originated

[Paul Russell]

On 1/14/2009 4:04 AM, David Wilson wrote:
> On Tue, 2009-01-13 at 20:46 -0500, Rich Kulawiec wrote:
>> On Tue, Jan 13, 2009 at 07:13:39PM -0600, Gordon Peterson wrote:
>>> That's a bogus argument.  You're basically saying that "someone else  
>>> will probably pick up on this" and using that as a (lame) excuse to lob  
>>> a grenade their way.
>> Perhaps you should review the SMTP protocol: sending a 5XX response
>> *refuses* delivery of a message.  It does not transmit (or retransmit)
>> a message.  It is difficult to see how one can be accused of "lob[bing]
>> a grenade" when one has never taken possession of it.
> 
> Because of the normal action of an MTA when it receives such an 5XX
> response, i.e. it sends a non-delivery message, normally containing the
> message, to the return path address. If that return path address is
> forged, then the infection is bounced elsewhere. That is the grenade.

The grenade was not lobbed by the MTA which issued the 5xx response; it was
lobbed by the MTA which previously accepted the message from some source and
attempted to deliver it to the MTA which issued the 5xx response during the
SMTP session.

-- 
Paul Russell, Senior Systems Administrator
OIT Messaging Services Team
University of Notre Dame
prussell at nd.edu