Simon Lyall wrote:
> On Fri, 15 May 2009, Chris Hoogendyk wrote:
>   
>> I use milter-greylist [...]
>> It's a royal pain in the butt dealing with all
>> the emails that all of my users try to send, and undoubtedly lots of it
>> falls through the cracks. There are a lot of non-compliant mail servers
>> out there -- big ones as well as small ones -- that fail for one reason
>> or another. Some have their queue runners botched up so that, when
>> greylisted, they don't come around to resend for many hours.
>>     
>
> Let me see, you're the one that is giving a temporary failure to every 
> incoming email and YOU are complaining about "non-compliant mail servers" ?
>
> It's like returning a busy signal to all incoming phone calls and assuming 
> that "The important ones will just ring back" so they will get though. But 
> you also assume:
>
> 1. The will call back *exactly* between 1 and 3 minutes later
> 2. You will see exactly the same caller-id second time around.
> 3. They will bother calling back at all.
> 4. Phone markets won't learn to do the same thing.
>
> The fact that you are complaining about how much work it is indicates to be 
> that you didn't research the pros and cons of the anti-spam method in the 
> first place.

You might need to do some research yourself before lashing out at someone.

What is non-compliant about a temp fail?

Standards compliance includes resending after a temp fail. The most 
common reason for not resending is that the sender is a compromised 
machine acting as a spam bot and is just blasting out messages, not even 
waiting for any interactions from the receiving end.

As for how it works, it would be absolutely ridiculous to require a 
response "*exactly* between 1 and 3 minutes later." Typically, the temp 
fail is configured to say, "try again in", say, "15 minutes" (or 3, it's 
a configurable number). But it isn't required that they respond that 
quickly. They could respond in an hour or a few hours, as long as it is 
beyond the 15 minutes and before some limit. That limit is also 
configurable (perhaps set to 20 hours). But, how long they take to 
respond is a function of their server, not of the greylisting 
configuration. Then, once you've accepted a connection, it is usually 
whitelisted for a while (again a configurable number, but often a couple 
of days), and that typically gets renewed whenever another connection is 
accepted.

Our implementation of milter-greylist resulted in a huge decrease in 
spam. The vast majority of mail servers deal with it properly.  Those 
that don't can be a pain in the butt, but it is much less of a pain than 
having everyone in your department screaming about the volume of spam.

We also frequently review, adjust and change our spam tools. It would be 
beautiful if we were in a world where we didn't have to waste time on 
security and spam prevention, but that isn't going to happen. It's a 
fact of life.


-- 
---------------

Chris Hoogendyk

-
   O__  ---- Systems Administrator
  c/ /'_ --- Biology & Geology Departments
 (*) \(*) -- 140 Morrill Science Center
~~~~~~~~~~ - University of Massachusetts, Amherst 

<[email protected]>

--------------- 

Erdös 4


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