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: > > Hello, > > 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. > > 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). > > 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. > > 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. > > My question is: do people still use graylisting? > > 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? > > Thanks in advance for sharing any thoughts / experiences. > > Cheers, > Ashley. > > -- > Ashley Aitken > Perth, Western Australia > mrhatken at mac dot com > Social (Facebook, Twitter, Skype etc.): MrHatken > Professional (LinkedIn, Twitter, Skype etc.): AshleyAitken > > 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 > > > > > _______________________________________________ > MacOSX-admin mailing list > [email protected] > http://www.omnigroup.com/mailman/listinfo/macosx-admin > _______________________________________________ MacOSX-admin mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-admin
