mouss wrote:
[snip]
While I am in, the recommendation in
   http://babel.de/batv.html
(cited from the implementations link) to use regular expressions based 
canonical breaks recipient validation and will cause backscatter. 
which breaks the whole purpose of BATV INMHO.
I was wrong here. I missed the trick to "stack" proxy_filter's.
My appologies.
Also, whatever the scheme is, there is another class of applications 
to think of. these are applications that use the sender address as an 
element to determine the "reputation" of a transaction (spamassassin 
AWL for instance). such apps should be made aware of the various BATV 
styles.