On Sun, 2010-06-27 at 20:09 +0930, Tim wrote:
On Sat, 2010-06-26 at 17:55 -0700, Craig White wrote:
> I use greylisting on all mail servers that I administrate and I
> specifically use one that maintains a list of well known smtp servers
> such as yahoo - it's a rather substantial list and maintained so that
> pretty much obviates your point #1.
>
(fussy servers)
> Point number 2 is well taken but in my experience, there aren't that
> many times this has come up (only once) and yes, that will cause an
> issue but again, I am able to whitelist the range of servers from that
> system.
>
(multi-rejects)
The trouble with those problems is *having* to do something about them,
for something that should really manage itself (servers retrying to send
to a supposedly busy server, or whatever other reason for a try later
response). Or, more to the point, knowing that you have to do so, in
the first place. Alright if you do so, but a problem if you don't, or
you're one of those people who think that all collateral damage incurred
when rejecting spam is acceptable. Especially so if you're trying to
mail someone, and something out of your control is getting in the way.
In theory, it's a clever technique. In practice, like all anti-spam
techniques, there are flies in the ointment. I don't mind people
suggesting it, or implementing it well. But it should be advised with
the appropriate precautions that you will need to manually add some
overrides. And unless you monitor logs (many won't), or hear about
problems in some other way (and many won't), you aren't going to know
that mail isn't getting through.
I don't hold with the contention that people should simply put up with
email being inordinately delayed because it doesn't have to be instant.
A few minutes isn't usually too much of a problem, but occasionally is,
and anything more than a few seconds for an email to whiz around the
world, in this modern era of fast computing, isn't really excusable.
Mail taking hours is unacceptable.
Having to change to another messaging format to overcome this isn't an
appropriate solution. There are plenty of cases where someone needs to
be sent something in writing, so the phone isn't appropriate, and
instant messaging tiny notes back and forth isn't, either.
----
10 different mail servers and have used greylisting for more than 5
years and only whitelisted a few named mail servers for one company to
whitelist a group of servers whose outbound mail queue could change the
sending server one time is hardly what I would call collateral damage
but you are so determined to make your weak point which I already
conceded but I know it is of little to no consequence.
Specifically, the whitelisted servers were all from a company that
actually does supposedly opt-in mail spamming and this customer of mine
was using them and it was slowing up their 'proofs' before they
unleashed on their mail list.
I have seen nothing in e-mail whose computing cost compared against spam
control has even come close to matching greylisting and while I can see
it would create problems for an ISP, corporate mail servers should not
live without greylisting.
Craig
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