--On 2 November 2007 04:24:11 -0700 ikearns <iankearns@???> wrote:
>
> Hi Ian
>
> Ultimately we have a platform that accepts mail from users on our IP
> allocation and also for domains of our users. This mail is then scored
> depending on the likelihood of it being SPAM. A central filtering platform
> will then take out mail that breaches this threshold. This accounts for
> taking out about 80% SPAM. This mail is then black holed.
This isn't a good place to be starting. I'd advocate getting rid of that
"platform", especially if it isn't configurable. At the very least, you
should be doing the checks that you describe below *before* email reaches
this "platform". Blackholing spam isn't a good idea, because nobody gets to
see the false positives. The best thing you can do with suspected spam is
to reject (not bounce) it, because then the sender gets to know about it.
> However any mail that does get through that is destined for a resolvable
> email address will then be delivered to the back end server(s) via and
> Exim box running manualroutes. Should this message be undeliverable
> (through the mailbox not existing) then this is sent back to the sender.
> I believe this is common practise and as describes, required as a NDR.
It is common practice, but it's highly undesirable. Instead, you should be
rejecting this email on your MX host. When you reject an email at SMTP
time, on your MX host, then you don't generate an NDR. If the message is
spam, then the sending server won't generate an NDR either, otherwise it
should.
> As our off-network mail is delivered from a small cluster of servers we
> keep finding that these servers are listed on the likes of SpamCop which
> then disrupts delivery of legitimate mail to our users.
This doesn't surprise me at all.
> We are looking at putting in a new anti-spam application shortly but in
> the meantime we need to try and filter out what are legitimate NDR's and
> which are bounced SPAM messages
This is a waste of time. You need to not accept spam messages, then this
problem will go away. It might be better simply to stop sending NDRs for
the time being.
>
>
>
>
> Ian Eiloart wrote:
>>
>>
>>
>> --On 31 October 2007 13:19:09 +0000 "Phil (Medway Hosting)"
>> <phil@???> wrote:
>>
>>
>>> In the words of Shaggy - It Wasn't Me !!!
>>>
>>> Original question was from "ikearns".
>>>
>>
>> Sorry, Phil.
>>
>> Ikearns, what exactly are you trying to do?
>>
>> --
>> Ian Eiloart
>> IT Services, University of Sussex
>> x3148
>>
>> --
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>>
>
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> Nabble.com.
--
Ian Eiloart
IT Services, University of Sussex
x3148
