smtp server test?

[Scott Silva]

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Joe Smith wrote:
> Any sendmail experts know of a milter that will check an inbound
> connection for a listening mail server?    Gotta be 90+ percent of
> spammers and virus connections don't have a listening smtp server.
>
I'm not sure if RFC's require a sending SMTP to also be a receiver.
Some large senders probably have separate sending and receiving mailers,
and you would get some false positives.
You could test for reverse-resolution, but there are a few legit.
mailers that have that broken also.



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