Ravi shankar wrote:
SMTP is currently a push protocol and is initiated by the the sender, no controlling that fact. But it is possible to overcome the relay problems, IP spoofing and domain impersonation etc, by making the servers pull the mails.
<http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US6192407> -- Dave Crocker Brandenburg InternetWorking bbiw.net