spamassassin not lethal anymore

James B. Byrne byrnejb at
Thu Jan 12 23:07:16 UTC 2017

On Wed, January 11, 2017 20:34, Russell L. Carter wrote:
> On 01/11/17 17:24, Kurt Buff wrote:
>> Snippety snip...

>> A secondary MX that refuses mail when the primary is up and running
>> foils one of the favorite tactics of spammers - they will often
>> target
>> the secondary MX because those are often not as up to date with
>> anti-spam measures. Most spambots try one MX, one time only.
>> Many spambots will try that secondary MX, get refused with a 4xx
>> error, and not bother to try the primary MX at all.
>> It can be a big win, in the right situation.
> Ah.  Awesome.  How do I do that?

If you have control over your forward zone DNS then you can simply
create a bogus MX record with a lower priority (higher number) than
any of your real MX records.  	172800	IN	MX	30  	172800	IN	MX	50  	172800	IN	MX	70  	172800	IN	MX	90

;# is not real - no listener at this address.   IN      A

There is nothing listening at on port 25 so the spammer
generally just goes away.

If you wish to get fancy then you can honey-pot the source address
instead.  The assigned address could be your own or be one of the
public junk mail submission addresses a la project honeypot.  Just
make sure to clear this redirection with the intended recipient before
doing so.

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James B. Byrne                mailto:ByrneJB at
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