On 23 Aug 2013, at 02:27, keld(_at_)keldix(_dot_)com wrote:
Just a thought I had for spam detection: what about testing if you could
connect to port 25 on the sending MTA? Zombies behind a NAT would not be
able to be reached. I think there are some web-based mailers that could be
but maybe one could make a whitelist for those. Is this a known
scheme, and what are the pros and cons?
I've often wished SMTP had the equivalent of "dial back" that is in XMPP. But
it's too late to be worrying about that now, because it means an extension, and
now you've got the whole problem of interoperability … again.
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