March 25, 2008
9:33 a.m.
Jo Rhett wrote:
On Mar 24, 2008, at 6:45 PM, Mark Sapiro wrote:
I still don't get what you mean by "properly deal with DSNs". Are you saying that an MTA should never return a DSN? It should either reject the mail during the incoming SMTP transaction or forever hold its piece?
Yes. And not just me, but a dozen different blacklists. RTFM "backscatter"
You can however safely send a DSN if an SPF[1] check for the incoming message passes.