> John Conover writes:
> > As a matter of policy, is it reasonable to reject messages that fail a
> > reverse DNS lookup on HELO's FQDN/authentication?
>
> No.
Indeed. Nevertheless, I think some elaboration will make the following
answers easier to understand to less experienced mail managers.
> Neither is it reasonable to reject messages from a host whose reverse
> DNS hostname lacks an MX record.
For instance, if a sending machine is only known to an organization's
internal name servers, but somehow its hostname is used in outgoing
messages, is it reasonable to block it? I would like to :>, but in
fairness, I can't :(
>
> Neither is it reasonable to reject messages from a host which isn't
> running an SMTP server.
Some organizations run incoming mail server(s) and outgoing mail server(s).
The later often do not run SMTP. But they do send out messages. Can
you block them, no.
>
> Although I've been sorely tempted to implement both of these.
8-) Likewise. I wish I could, it would make spam filtering a much
easier (if less fun :> job to do.
Chin Fang
[EMAIL PROTECTED]
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