Re: spamcop blacklisting servers for misdirected DSN messages

[Carlos G Mendioroz <tron@huapi.ba.ar>]

What Spamcop is doing basically implies that all forms of relaying are 
to be forbidden, or accepted to be unreliable to the point of not 
knowing if it fails.

No one should accept a mail that can not be delivered to its 
destination, needs full knowledge of destinations by MTA.

This includes backup MXs, domain gateways (are there any still there ?), 
etc.

This can be solved by authentication (which does not apply to global 
mail coming to a site, does it ?) or by forcing the sender to check 
later for delivery state, as there is no way of going back to the 
sender. We don't KNOW who the sender is, after all.

Oh well, no news here, just mumble on where the mail is going to be real 
soon now...


acli@ada.dhs.org wrote:

> In article <S339838AbUCJTxe/20040310195334Z+134@SMTP.Morgan-Systems.com>,
> Neal Morgan <Neal@Morgan-Systems.com> wrote:
> 
> 
>>For what it's worth, I use a rather non elegant approach to
>>handle this.  I have a scheduled job that finds "user doesn't
>>exist" messages from syslog, bounces those against known
>>valid aliases, taking the truly bad addresses and dynamically
>>re-building the smtp-policy.spam file.  The bounce against
>>valid aliasses allows me to remove bad addresses if the alias
>>has subsequently been made valid.
>>
>>This doesn't prevent the first attempt to reach a bad address,
>>but does prevent subsequent ones, because zmailer will
>>reject the message if the "to address" is contained in the
>>smtp-policy.spam file.
> 
> 
> One problem with this is that some backup MX's (e.g., hosted
> by the ISP) are misconfigured in such a way that they will say
> valid users do not exist, but the primary MX (e.g., hosted by
> the actual company) is correctly configured. So whenever the
> primary goes down, valid users will be flagged as invalid.
> 
> 
> 

-- 
Carlos G Mendioroz  <tron@huapi.ba.ar>  LW7 EQI  Argentina

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