Re: Email Graylisting

I disabled greylisting on a 10.6.8 server because I was getting =
complaints about lost or slow  mail from our campus primary mail =
service, Google.  It may be exactly as described below by Markus. =
Fortunately there doesn't seem to have been a large upswing in spam. I =
am surprised that the filters let through a message that claims to be =
from that country in Africa gave us 419.

 - Milo

On Apr 5, 2013, at 10:55 AM, Markus Ruggiero wrote:

> Problem with greylisting is as follows:
>=20
> 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.
>=20
> 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.
>=20
> Have fun
> ---markus---
>=20
> On 05.04.2013, at 14:34, Ashley Aitken <[email protected]> wrote:
>=20
>>=20
>> Hello,
>>=20
>> 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.
>>=20
>> 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).
>>=20
>> 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.
>>=20
>> 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.
>>=20
>> My question is: do people still use graylisting? =20
>>=20
>> 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?
>>=20
>> Thanks in advance for sharing any thoughts / experiences.
>>=20
>> Cheers,
>> Ashley.
>>=20
>> --
>> Ashley Aitken
>> Perth, Western Australia
>> mrhatken at mac dot com
>> Social (Facebook, Twitter, Skype etc.): MrHatken=20
>> Professional (LinkedIn, Twitter, Skype etc.): AshleyAitken
>>=20
>> Dropbox stores your files so you can access from any computer.  Get =
it (and extra space for both of us) for free!  Go to =
http://db.tt/geb9RWb
>>=20
>>=20
>>=20
>>=20
>> _______________________________________________
>> MacOSX-admin mailing list
>> [email protected]
>> http://www.omnigroup.com/mailman/listinfo/macosx-admin
>>=20
>=20
> _______________________________________________
> MacOSX-admin mailing list
> [email protected]
> http://www.omnigroup.com/mailman/listinfo/macosx-admin