Spam and sieve vacation

Tomas Lindroos DC skitta at
Tue Aug 28 10:14:25 EDT 2007

On Mon, 27 Aug 2007, Janne Peltonen wrote:

> 5/week? Whee. We might achieve something remotely approaching that with 
> personalized bayesian filtering (a multi-discipline, internationaly 
> connected university receives quite a lot of ham that looks very much 
> like spam, so we are a bit paranoid about false positives).

Due to spam levels we have been disallowing "vacation" the last 4-5 years. 
This summer we made it possible for our users to enable an autoresponder. 
We use greylisting and spamassassin with bayesian filtering, and we are 
quite low on spam ending up in users inboxes, and also on false positives.

We don't provide vacation via sieve though, we considered it not being the 
IMAP server that should send the answers. Instead we use a home-grown 
python script on a smtp server.

Since may 73 people have actually used this service. During the last 12 
weeks 17129 messages were not answered, of which 3002 had a spam level of 
3 or more and 1103 messages would have been answered if they had come from 
inside addresses (our users can choose to answer only inside our domain).

2570 auto-replies were sent. Looking at the logs it seems that perhaps 25% 
of these replies should not have been sent and most of these can actually 
be caught with some more filters in the python script. That makes 200 
backscatter messages a week for us this summer - probably worth it, and 
the filters can be improved.

 	checking out rfc3834 right now - we seem to be fairly
 	compliant :)
  Tomas 'Skitta' Lindroos.
  UNIX systems administrator, Åbo Akademi University, Computing Centre
  skitta at, +358-40-5177716

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