[Greylist-users] Important emails are delayed by up to fou

[Dennis Wynne]

That is one of the downsides to using greylisting.  I had to "fight" over this 
as well since my bosses thought that e-mail was something that always went 
through and did so right away. In fact, if your Internet connection is down or 
your mail server is down you will never see mail from folks who do not retry 
the send.

What I ended up doing was producing a daily report showing any mail that 
bounced (had passed count = 0) so everyone could look it over. If they saw 
something, like AA or SWA servers that retried on different IP and/or with 
different mail from then we white listed them. Any customer servers got white 
listed as well.

To make this more immediately available, I got some php code from a list 
member here and put up a web page the users could check at any time so each 
user could see his/her bounced mail. In the case where there was something 
important coming in and they saw it on the real time php page, they simply 
asked the sender to send it again. If the other end sends a message twice and 
it is within the "window" (in my case > 1 min < 5 hours) then the 2nd message 
is taken as the retry and goes right through. Whenever their mail server 
retries, you get the first send message.

You could also work with your users to produce a list of their valid contacts, 
check the current IPs in your mail server, and pre-white list them before you 
put up grey list.  I wanted the system to work this out for itself, so I did 
not bother but if you choice is "don't miss a single important e-mail or don't 
put up grey list" then I would do that.

Dennis

>===== Original Message From greylist-users at lists.puremagic.com 
(chuck.amadi at rokcorp.com, Greylisting Use) =====
>Hi List
>
>I posted a email regarding if
>
>Hi List
>
>A colleague has some reservations about greylisting in general because
>of the inherent delays that would be introduced.
>
>My Colleague views below:
>
>I am concerned that the top management will not be impressed when
>important emails are delayed by up to four hours, especially since that
>delay is dependent entirely on the third party's mail server retry
>schedule, and thus beyond our control to configure.
>
>I have installed postfix and postgrey at my last employer and I didn't
>see any issues but are the above reservations warranted As I thought the
>longest possible delay
>in 5 mins using the default settings and once whitelisted will never
>have to go through the grey listing process again plus the the fact I
>could also pre add any important email
>address or domains to whitelist_clients list which again avoid going
>through grey listing process.
>
>Please advise and if possible any good links So I can read and digest as
>I personally I would like to implement grey listing as part of our
>strategy to
>reduce UCE.
>
>Cheers
>
>--
>Chuck Amadi
>ROK Corporation Limited
>Ty ROK,
>Dyffryn Business Park,
>Llantwit Major Road,
>Llandow,
>Vale Of Glamorgan.
>CF71 7PY
>
>Tel: 01446 795 839
>Fax: 01446 794 994
>International Tel:   +44 1446 795 839
>
>email: chuck.amadi at rokcorp.com
>
>This email is confidential to the addressee only. If you do not believe
>that you are the intended recipient, do not pass it on or copy it in any
>way. Please delete it immediately.
>
>
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