[Asrg] where the message originated (was: DKIM role?)

[SM]

At 12:10 08-01-2009, Douglas Otis wrote:
>There are methods that can be used to limit risks related to
>whitelisting domains.  Often these involve capturing prior
>conversations and noting where the message originated.  The locations
>might then be expanded to CIDRs, routes, or acquired address lists.

Is it that important to note where the message originated?  Although 
the where is commonly used as input for lack of a better reference 
point, it can be a problem when renumbering a network or for mobility.

Did this message reach you because:

  1. it came from the irtf.org domain

  2. it came from the ASRG email address

  3. it came from an IP address associated with 1 or 2

  4. it came from a CIDR block you view as "safe"

Regards,
-sm

P.S. You may decide not to answer the above question to limit the 
risks related to whitelisting.