Can we reject mail yet still deliver it?

Vernon Schryver vjs@calcite.rhyolite.com
Mon May 6 19:17:42 UTC 2002


> From: "Earl A. Killian" <earl@killian.com>

> Jeff Wiegley, Ph.D. writes:

>  > I like the idea of saving spam for reasons of accountability,
>  > prosecution and intrusion detection.
>
> The -l option of dccproc does that.

See also `dccm -l`
Then look in the log directories.

>  > But I would rather my sendmail respond to spam requests with a
>  > ERROR:"550 We don't accept mail from lower-than-dirt spammers"
>  > so that they get the message.
>
> They probably won't ever see the message.

Because spammers often but not always arrange to not receive 
notices of delivery failure.

>                                            However, rather than the
> above, you might consider something more legalistic, since you mention
> prosecution above.  For example, give a URL to a web page with your
> unsolicited bulk email policy, which states that they owe you $500 per
> message, or something.  Like shrinkwrap software licenses, you could
> try to assert that by sending mail to your site, they have accepted
> your policy.

Fat chance of actually collecting anything.

 ...

] Is it possible to have sendmail respond with a 550 rejection error
] but still deliver the article to the recipient?

By the nature of the SMTP protocol, that should be impossible.  A
rejection error message means that the message is rejected instead of
delivered.  However, as noted, you can look in the DCC log files to
see what was rejected or discarded.


] I want to modify the X-DCC-header string to look like:
] X-DCC-XXX-Metrics: XXX 1012; Body=1 Fuz1=1 Fuz2=many Action=reject
] 
] So that my mail filters can be specified to search for all DCC rejected
] mail accurately.

The X-DCC headers on the next version of the DCC client programs will 
contain the string "bulk" if the message is bulkly.

However, that does not seem useful for the stated purpose.  Mail rejected
by dccm can't be filtered in the normal sense because it is not delivered.
However, you could look at last line or two in dccm log files which
says something like "result: reject" for rejected mail.

It is straight forward to write regular expressions to match X-DCC lines
that would be rejected by likely thresholds.
Consider the pattern (Body|Fuz[1-4])=(many|[5-9][0-9]|[0-9]\{3,\})


Vernon Schryver    vjs@rhyolite.com



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