william(at)elan.net wrote:
The better solution is to have standard that allows ISPs
to specify which of their ips should and should not be
used for outgoing email. The best is to use SPF records
for this purpose adding them with new "PTR" scope to name
pointed by ip PTR.
Sounds like MTAMARK going SPF (spf2.0/ptr). That's a rather
expensive solution compared with DUL-lists. But maybe it
could be combined, the MX continues to use the DUL list,
the DUL list uses MTAMARK (resp. spf2.0/ptr) as one of its
sources.
Discuss it on the ASRG list, maybe, the author of MTAMARK
reads it (and he's no SPF fan, so this could be fun ;-)
Bye, Frank