[Pine-info] Filtering unusual ASCII code
Lucio Chiappetti
lucio at lambrate.inaf.it
Tue Aug 29 05:17:53 PDT 2006
On Tue, 29 Aug 2006, Cornelius C. Noack wrote:
> A week ago, I submitted the following question to the list, asking for help,
> but received no answer so far. So I'll try again:
Strange, I believe I replied privately, and I also saw some more traffic
on the list on the subject. Cannot swear it was you or somebody else with
a similar question. I'll try to rewrite my answers.
> Since I never - in over 8 years - ever saw this code set (1022)
> used in any serious mail to me, I would like to filter my incoming
> mail for any that uses the iso 1022-jp code set in the subject field.
> (1) is there any argument against doing that?
None if you do not have regular correspondents in Japan which use such a
character set.
> (2) how do I set the filter accordingly ? I tried looking for the
Personally I believe it's a bad idea (or a last resort) to do
post-delivery filtering and therefore I've never done it in pine.
What I used in the past (still active but less used, read on) was
extensive use of procmail to do filtering at delivery time (what I do is
described in http://sax.iasf-milano.inaf.it/~lucio/Procmail/ ... but for
the installation and configuration of procmail you have to look to other
resources on the net).
An hint however is to use the full header command in pine to discover what
is exactly the offending string. I used that to debug my procmail rules.
> And here are 2 additional questions
> (2a) the same applies to mail sent with the [GB2312] code set. But
> the name of that looks like a Great Britain code set (!?), so I
It's not Great Britain, it's some chinese code.
It is included in the set of procmail rules I use for foreign charsets
http://sax.iasf-milano.inaf.it/~lucio/Procmail/rc.chinese (note I did not
write most of it, just adapted it from an extensive procmail package
called SpamBouncer.
> (3) another frequent case of spam is mail with 'Re:___' ('___'
If you are seriously intending to reject spam, you should resort to more
aggressive means which act at delivery or even before delivery. I found
that mantaining the content-based part of my procmail rules was too much
of a hassle (and one is always "behind" the spammers).
A thing like DNSBL (black lists of mail sites) at sendmail level is quite
more effective (in fact we were running that institute-wide ... my rules
were just filtering the residual spam).
A tool like spamassassin is even much more effective. Since a couple of
months we are running institute-wide a sendmail milter based on
amavisd-new calling spamassassin (which does DNSBL, URIBL - i.e. blacklist
of URLs referred by spammers -, content analysis and network tests like
razor and DCC, and then weighs and combines them all), and now my rules
are triggered very unfrequently. For our entire institute the percentage
of good mail is 15% of what we receive. 46% is rejected by spamassassin,
16% is addressed to non-existant users, 6% is rejected by the greet pause
mechanism and the rest by other sendmail checks.
Installing a milter should be done at central level, maybe it is best to
talk with your system managers about using an aggressive antispam policy.
However spamassassin with all plugins can also be installed privately on
your workstation (as milter if you are root, otherwise it can be installed
at user level as delivery-time agent called via procmail using a single
simple rule).
Only if you can't do ANY of the above you should resort to post-delivery
filtering in pine, on which others may be able to assist better than me.
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Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy)
For more info : http://www.iasf-milano.inaf.it/~lucio/personal.html
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