Re: [Exim] Yahoo `421 VS2-IP Excessive unknown recipients - …

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Author: Matthew Byng-Maddick
Date:  
To: exim-users
Subject: Re: [Exim] Yahoo `421 VS2-IP Excessive unknown recipients - possible Open Relay http://help.yahoo.com/help/us/mail/spam/spam-18.html (#4.4.5)'
On Wed, Feb 27, 2002 at 11:26:39AM +0000, Ian Jackson wrote:
> Does anyone else around here know anything about this behaviour by
> yahoo ? Is the 421 for excessive unknown recipients new ? How long


I don't know what else you could give, given the way their verification
works. I'm not saying that the verification is the right way to do it,
but as I mentioned in a previous thread, yahoo have always failed unknown
recipients after the final '.'. This makes any callbacks, whether from
exim itself or SAUCE, useless. The 421 seems like the correct thing to
do (similar, in a way, to SAUCEs own tricks) based on where the
verification occurs. A 550 seems wrong, and a 450 seems wrong, and it
obviously doesn't want to accept the mail because of the large number
of unknown users, so a 250 is right out.

> have they been giving the temporary failure code 451 after end of data
> for unknown recipients, rather than saying 5xx (I haven't been looking
> carefully enough to answer that myself) ?


I guess it is something to do with not doing verification at RCPT TO time,
and instead doing it after the final '.', though it seems to me that they
should be accepting the message in full and taking responsibility for
delivering the bounces.

> I've noticed for some time that I get a lot of bounced bounces for
> yahoo, partly because some (old and current) FAQ maintainer addresses
> are on my system and their autoresponders want to reply to all their
> mail, and yahoo don't reveal whether a recipient exists at RCPT time,
> so SAUCE's incoming recipient verification using reverse connections
> doesn't help.


I mentioned this in a previous subthread.

Yahoo are sucky. This is, as you know, not news.

MBM

--
Matthew Byng-Maddick         <mbm@???>           http://colondot.net/