Author: Andrew - Supernews Date: To: exim-users Subject: Re: sender callout shorcomings Was: Re: [Exim] sender verify vs. broken...
>>>>> "Giuliano" == Giuliano Gavazzi <eximlists@???> writes:
>> There's one known case (though it has not actually happened yet to
>> my knowledge) where enabling sender callout will cause a site to
>> fail to receive mail from us; if you make the callout attempts
>> from an IP address which is listed on a dynamic-IPs list
>> (currently dynablock.easynet.nl), or on one of a number of proxy
>> and spam-sources blacklists, then the default timeouts will be too
>> short to get the successful response from the verification, and
>> you'll just defer the message forever unless you lengthen the
>> timeout (to at least a couple of minutes) or set defer_ok.
Giuliano> this is because, apart from the HELO phase, a server should
Giuliano> offer a clean path to verification using a null sender.
I think you missed my point completely.
We do not currently reject any mail at the HELO or MAIL FROM stage,
with the exception of Cacheflow proxies which are not permitted to
connect at all. However, we do force substantial delays on certain
hosts, and those delays _will_ cause sender callout verification to
time out unless the timeout is increased from the default.
