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Article: 1173
From: Steve Freegard
Date: 2006-10-09 17:45:25 -0400
Subject: Re: milter-sender greylist/yahoo problem

Removal...........: milters-request@milter.info?subject=remove
More information..: http://www.milter.info/#Support

Hi Chris,

> Now for my question.
> Are there other options I should try to callback to yahoo/ebay that might 
> work?

I'm afraid not -- Yahoo and Ebay are accept-then-bounce systems, so 
call-backs do not work for them, which is why milter-sender is falling 
back on it's second method of greylisting it instead - for example:

[root@mail ~]# host -t MX yahoo.com
yahoo.com mail is handled by 1 mx3.mail.yahoo.com.
yahoo.com mail is handled by 5 mta-v1.mail.vip.re3.yahoo.com.
yahoo.com mail is handled by 1 mx1.mail.yahoo.com.
yahoo.com mail is handled by 1 mx2.mail.yahoo.com.
[root@mail ~]# telnet mx1.mail.yahoo.com 25
Connected to mx1.mail.yahoo.com (
Escape character is '^]'.
220 mta243.mail.re2.yahoo.com ESMTP YSmtp service ready
250 mta243.mail.re2.yahoo.com
250 null sender <> ok
RCPT TO:<blahblahsdjslkdf@yahoo.com>
250 recipient <blahblahsdjslkdf@yahoo.com> ok
354 go ahead
This is a test message -- Yahoo will reject this after the ending . 
554 delivery error: dd This user doesn't have a yahoo.com account 
(blahblahsdjslkdf@yahoo.com) [0] - mta243.mail.re2.yahoo.com
221 mta243.mail.re2.yahoo.com
Connection closed by foreign host.

Sender verification can only work on systems that reject recipients at 
the RCPT TO: stage, so when doing the call-backs milter-sender pretends 
to send a message to the actual user, and if this is accepted it 
'invents' a second username and tries to send this as another recipient, 
if this is recipient is accepted then milter-sender marks the domain as 
blindly accepting messages addressed to their domain and falls back to 
greylisting the message instead.

/etc/mail/access entries of:

milter-sender-Connect:yahoo.com		OK
milter-sender-Connect:ebay.com		OK

Would be sufficient to skip greylisting of a mail sent through machines 
on the yahoo.com or ebay.com domains while still greylisting messages 
claiming to be from either of these domains but not being sent via 
servers outside of their domains (which is a nice way to handle these IMHO).

Kind regards,

Steve Freegard
Fort Systems Ltd.

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