Re: Email Graylisting

Problem with greylisting is as follows:

The sender mail server receives a replay telling it that the receiving =
server (your machine) is not ready for incoming mails and that it should =
try later. When the next try happens you mail server accepts that =
message. This is done on the basis that it is the same sender server and =
the message is destined for the same user mailbox. How long the sender =
waits for the next try is completely out of your control. On large =
sender domains the next try might come from a different mail server and =
thus is not recognised a second try but is again a first try and will be =
rejected. Next try is hopefully from one of those two sender servers but =
can happen that a 3rd server tries to send. Rejected again. The sender =
server cluster may eventually decide that it need to give the receiver =
(your server) more time to become ready for incoming mail. And the game =
continues.

I have greylisting enabled on my server and am quite happy with the =
results. Cut spam down to 20 per cent of what it used to be. Once or =
twice in a year I suspect a lost message, but cannot remember having had =
any real problem.

Have fun
---markus---

On 05.04.2013, at 14:34, Ashley Aitken <[email protected]> wrote:

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> Hello,
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> I've been using Mac OS X Server 10.6.x Snow Leopard for a number of =
years and never really had problems with email graylisting.  Yes, mail =
sometime took minutes or a few hours to arrive when signing up for Web =
site, etc. But generally speaking most personal emails came through =
quite fast, at least after the first one.
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> Recently, it seems with one particular domain (I have check the domain =
MX setup and DNS) personal emails are taking a long time to get through, =
e.g. 10-24 hours.  This can be frustrating now as many people, even in =
business, assume email is pretty much instantaneous (even though I =
believe it's never guaranteed to be).
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> My feeling is that this is a problem with the sending side, i.e. they =
aren't retrying to send the email soon enough or after it is rejected.  =
But I haven't perceived this problem with my other domains.  That said, =
perhaps  it is just this new domain that is getting a lot of email from =
new people.
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> LuKreme has indicated, in an earlier thread, that he had problems with =
amazon.com and banks.  Personally, I haven't noticed that (but missing =
emails may be harder to notice than delayed ones). I can understand how =
it could be a problem, again if the sender side didn't co-operate.
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> My question is: do people still use graylisting? =20
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> It seems to me a pretty effective way to prevent spam but them I have =
to re-evaluate it if it is going to cause these sort of problems.  We =
tend to be somewhat concerned these days about email receipt because of =
this.  Perhaps graylisting has had its day, and we need to move on to =
some other form of spam protection?
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> Thanks in advance for sharing any thoughts / experiences.
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> Cheers,
> Ashley.
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> --
> Ashley Aitken
> Perth, Western Australia
> mrhatken at mac dot com
> Social (Facebook, Twitter, Skype etc.): MrHatken=20
> Professional (LinkedIn, Twitter, Skype etc.): AshleyAitken
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(and extra space for both of us) for free!  Go to http://db.tt/geb9RWb
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