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Article: 79
From: Anthony Howe
Date: 2004-09-23 04:48:48 -0400
Subject: Re: milter-sender 'not answering' response

Removal...........: milters-request@milter.info?subject=remove
More information..: http://www.milter.info/#Support
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Adam Gibson wrote:
> Does anyone know the specifics of how milter-sender is supposed to 
> handle servers where the primary MX server(s) are not online so 
> connection attempts to them time-out?  Shouldn't this cause the 
> grey-list routine to kick in?  I am seeing quite a emails where we 

Grey-listing only kicks in when the call-back test results in an 
inconclusive answer: both an intended false address and the test address 
return 250 responses for the RCPT command - yahoo.com is a good example 
of this, so too are many secondary MXes that blindly accept anything for 
their domains.

If all the MXes, primary and secondary, upto MxCallBackMaxAttempts for a 
domain fail to answer, then they are assumed bogus and the message is 
rejected with "not answering".

> constantly give the response of 'not answering' from automated 
> systems(incoming mail from automated aol password reset requests, 
> entrust cert renewal reponses, etc).  The mail servers try to resend it 
> later but we still give the same response.

If you haven't already, add SPF records for your domain. AOL has many 
multi-homed MXes and one or more of them usually answers. AOL may  be 
rejecting the call-back based on lack of an SPF record. This is not certain.

> 
> milter-sender config:
> MilterSocket=unix:/var/lib/milter-sender/socket
> DeferMailReject=0
> GreyListRejectCount=5
> GreyListBlockTime=300

Try:

	MxCallBackMaxAttempts=4

Also maybe increase

	SocketTimeout=180

However, when you increase timeouts, make allowances for this in the 
INPUT_MAIL_FILTER F= R: timeout value too so that Sendmail will wait on 
the milter a little longer while it tries to connect.

	R: approximately equals (MxCallBackMaxAttempts * SocketTimeout)

-- 
Anthony C Howe                                 +33 6 11 89 73 78
http://www.snert.com/       ICQ:
7116561         AIM: Sir Wumpus

            "Once...we were here."  - Last of The Mohicans


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