Re: [Exim] permanent failure for spam

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Autor: Ron McKeating
Data:  
Para: Phil Chambers
CC: Exim-Users (E-mail)
Assunto: Re: [Exim] permanent failure for spam
On Wed, 2003-11-05 at 17:34, Phil Chambers wrote:
> > Ron McKeating wrote:
> > > Now it seems that btinternet are doing spam filtering at the smtp
> > > transaction and if it identifies a spam it breaks the connection with a
> > > defer. Is this normal? we are thinking of setting up exiscan to do this
> > > to emails with big spam scores but we were planning to do a deny, eg a
> > > 550 permanent error. The way bt are doing it, the email sits in our
> > > queue for 8 days and we constantly re-attempt to deliver it.
>
> I am curious to know if the messages are spam. If they are then perhaps you deserve
> to have messages clogging up your queue. If not, then it looks as if BT's
> spam-checking is up the creek and it might be worth contacting their postmaster to
> let them know.
>
> Phil.


Yes Phil they are indeed all spam. We scan all incoming emails with
spamassassin, and do detect huge amounts. See our mailrouter spam
detection stats at http://mrtg.lboro.ac.uk/mail/bill-spam.html.

But we mark all email that scores over 6 with a spam header, then users
have a file called .specialfilter (which they set up via a web page
interface we designed for spam filter choices) which will have one of 3
choices in it, deliver all my email and do not touch it, hide all spam
tagged email in a directory called SPAM in user home and delete any over
21 days old (this is the default, users cannot see it but we can trace
lost emails if they ask) and finally drop spam tagged email into a
folder called filtered_SPAM which the user can see as a mail folder.

We do go to a lot of trouble to detect spam and give our users the
option to be protected from it. But if users are forwarding their email
to home what can we do about that ? The forwarding happens before local
delivery and even if the user has username-noforward in their .forward
file as well as the other address they want delivered to, we can only
act on the local copy of the email being delivered to us.

On the other hand, we are kindly putting in a spam header for btinternet
to work with before we forward it :-)

I would be quite keen to hear if anybody has a neat solution so that an
email marked as possible spam is not forwarded. The trouble is we have
to give our users the choice, if they do not want their email spam
filtered then we cannot do it, they pay our wages and we work for them.
If our academic staff in social science are doing research into child
porn, or our chemistry department into pharmacuticals we could end up
blocking an awful lot of valid email.

As a University we have 4000 staff and 18000 students, it would be very
difficult to have one rule for all.

So Phil in a word yes, they were all 130 of them spams, and if you think
I should burn at the stake, while ravenous crows peck out my eyes
(surely only ravens could be ravenous?) then so be it. If any great
email master for whom the spam force is strong wants to pass me their
wisdom I will be happy to listen.

Ron
> ---------------------------------------
> Phil Chambers (postmaster@???)
> University of Exeter
>
>
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