RE: [Exim] lookuphost, MX and A records discrepancy ?

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Author: Bernard Stern
Date:  
To: Philip Hazel
CC: exim-users
Subject: RE: [Exim] lookuphost, MX and A records discrepancy ?
On Fri, 14 Jul 2000 20:14:49 +0100 (BST) Philip Hazel wrote:

> On Fri, 14 Jul 2000, Bernard Stern wrote:


>> news_bounce:
>> driver = lookuphost
>> domains = *
>> local_parts = news
>> condition = ${if and {{> {$message_age}{43200}}{eq {$sender_address}{""}}} {yes}{no}}
>> # 43200 s = 12 h
>> transport = trash
>>
>> This works well, but apparently only for domains that have an
>> MX record. This does not work for other domains (mmhhh... I wrote
>> apparently because I did some checks but I did not check every
>> instance of such hosts from my log files :-) ).


> I wonder... there are domains out there that don't have MX records, but
> whose zones are on broken name servers so that when you try to look up
> the MX record, you get a name server error instead of "no such domain".
> If this happens, Exim cannot proceed; it has to defer delivery and try
> again later. That would defeat this scheme.


Yes, I think I'm getting the point. I have looked at some more logs
and the error is either "connection refused" or "connection timed
out". So Exim doesn't get any SMTP return code and is bound to
try again.
The problem here is that these newshosts send out mail with
addresses related to themselves but are not configured for
receiving mail. Mmhhh... I can live with these NDRs cluttering
my queue, but I'd have loved to find some clean config
to trash them... more pondering needed, but this is not urgent.

(...)

>> So my question: is there an inherent difference in the treatment
>> of hosts with and without MX record using only these options?


> There should not be. Have a look at the log to see what the entries for


OK, this is what I wanted to know.

Well, it seems that I have only two other ways of trashing
non local messages based on local part.

1. re-route them on some other incarnation of exim listening
on another port and dealing with them accordingly.
2. place a request on the wish list to be able to use local
parts within the retry configuration. It somewhat beats
the golden rule that non local addresses should not be
decided upon based on local part.

Or maybe there is another scheme I haven't spotted yet?

Anyway, thank you Philip for your enlightment.

Regards,

Bernard Stern, SWITCH

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