The mailing list for listmasters using Sympa

[Patrick von der Hagen <address@concealed>]

Liam Kirsher schrieb:
[...]
> What's the best way to deal with this?
There is no best way. And there is always a bigger fish...
However, there are some possibilities.

> 1. Is there some way to configure Sympa to silently trash messages that
> are from people who are not subscribed to a list?
That could be done, but I'd consider it to be a kind of "last resort",
nothing one should start with.

However, when you look at your scenarii in ~/bin/etc/scenari, you can
modify your send.*-scearni. Copy the ones you intend to change to ~/etc/
first, otherwise future sympa-updates will overwrite your changes.

e.g. send.private says:
is_subscriber([listname],[sender])            smtp,smime,md5    -> do_it
is_editor([listname],[sender])                smtp,smime,md5    -> do_it
is_owner([listname],[sender])                 smtp,smime,md5    -> do_it
true()               smtp,md5,smime  -> reject(reason='send_subscriber')

change the last line to
true()               smtp,md5,smime  -> reject,quiet
and all non-subscriber-mails will be dropped.

However, I definitly DO NOT RECOMMEND to do something like that.

> 2. Alternatively, I notice that my spam scanner, Amavisd-new (+
> SpamAssassin, with Postfix) has the capability of doing SQL searches.  
> I'm wondering if I can't configure it somehow to check the sender
> against the Sympa list of users, and if no match is found, just drop the
> message.  That would stop the backscatter and relieve Sympa of having to
> process all those bogus messages.  Has anyone done something like this?
Currently sendmail and postfix can support the milter-protocol. It
shoudl be possible to create a milter-daemon performing the check you
mention, but the message should be rejected, not dropped.

I'll try to implement such a milter as soon as exim has milter-support,
but currently it is still lacking milter-support, so I'd have no way to
check a sympa-milter-implementation, thus I haven't started that project
yet.

However, I suppose postfix+amavis currently marks messages as "probably
spam"? Then you could do something like this:

match([header->X-Spam-Level],/\*\*\*\*\*\*\*+/) smtp -> reject,quiet
is_subscriber([listname],[sender])           smtp,smime,md5    -> do_it
is_editor([listname],[sender])               smtp,smime,md5    -> do_it
is_owner([listname],[sender])                smtp,smime,md5    -> do_it
true()           smtp,md5,smime  -> reject(reason='send_subscriber')

Messages considered to be spam are dropped, other messages from
subscribers are processed normally and non-subscriber-mail not
considered to be spam generates a bounce, explaining the rejection.

Currently, this is my preferred solution.

-- 
CU,
   Patrick.

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