Man, they'll try anything to hack your system...

[Bill McGonigle]

On Jan 27, 2006, at 13:30, Bill McGonigle wrote:

> I'd be happy to add a SpamAssassin or postfix rule to ignore mail from 
> senders with no reachable MX for a reply.

Found this for postfix:

   smtpd_sender_restrictions = reject_unknown_sender_domain

   Reject the request when the sender mail address has no
   NS A or MX record. The unknown_address_reject_code
   parameter specifies the response code for rejected
   requests (default: 450). The response is always 450
   in case of a temporary DNS error.

I bet the code for this directive could be adapted pretty easily to 
check for the three private ranges - call it reject_private_sender_mx 
or some such.  I'd give it a shot but I'm not on a current postfix 
quite yet.

-Bill

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