Problem with user emails sent using postfix smtp authentication blocked as spam

[Sergio Rabellino]

I do the same as suggested, requiring TLS authentication when sending 
email from outside my lan, an extra header field is set into the last 
Received header: for sendmail users the rule follow, where the bold 
words must be identical.

HReceived: $?{auth_authen}from $j ([${if_addr}])
         $|$?sfrom $s $.$?_($?s$|from $.$_)$.
         $.by $j (SENDMAIL)$?r with $r$. id $i$?{tls_version}
         (version=${tls_version} cipher=${cipher} bits=${cipher_bits} 
verify=${verify}$?{cn_subject} 
userCertificateDN=${cn_subject}$.$?{auth_authen} *YOURTOKEN* $. )$.$?u
         for $u; $|;
         $.$b

Then I set-up a sa rule as follow

header   AUTHENTICATEDUSER Received =~ /(.*)*YOURTOKEN*(.*)/
describe AUTHENTICATEDUSER Email Sender Authenticated by My Server
score    AUTHENTICATEDUSER -100.0

and all the emails sent through my SMTP authenticated session, will be 
automagically whitelisted.

Hope this helps.

Glenn Steen ha scritto:
> 2009/9/17 Neil Wilson <neilw at dcdata.co.za>:
>   
>> Hi guys,
>>
>> I've got a problem with a user sending email from a dynamic IP to his server
>> using SMTP authentication.
>>
>> His emails are being blocked as spam(score of 7) because of the dynamic IP
>> and reverse dns entries.
>>
>> I can whitelist his address, but the problem with this is that there are a
>> lot of faked sender address spam emails coming from the same address.
>>
>> I can reduce the points being allocated for each rule, but this will affect
>> all emails so will reduce the spam filtering efficiency.
>>
>> Any suggestions will be greatly appreciated.
>>
>> Regards.
>>
>> Neil.
>>     
>
> Either let the TLS authenticated sender (your user) bypass MS
> altogether (might be tricky getting that right:-), or use an SA rule
> to "counteract" the score penalty by way of some identifiable thing in
> the resulting headers.
>
> Cheers
>   

-- 
Ing. Sergio Rabellino

Università degli Studi di Torino
Dipartimento di Informatica
ICT Services Director
Tel +39-0116706701  Fax +39-011751603
C.so Svizzera , 185 - 10149 - Torino

<http://www.di.unito.it>

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