On Wed, Dec 11, 2013 at 9:34 AM, Timothy Murphy <gayle...@eircom.net> wrote:
> I have what I take to be the standard postfix/amavis/dovecot/spamassassin
> setup
>
> on my CentOS server, and as far as I can tell it is working fine.
>
> However, I must confess that I do not know how spamassassin is working,
>
> what it does with spam, whether this is fed to sa-learn and if so how.
>
> (I collect email with fetchmail from various mail-servers.)
>
Here is a really broad view of how we do it; I have a feeling
you might be doing the same:
1) Postfix receives email and then passes it to amavis. This talking
is done using a tcp port in the server
2) Amavis then grabs email and does check for viruses and spam, using
spamassassin
3) Spamassassin does its thing by reading each email and scoring it.
Its score is added to the header of the email
4) Amavis passes the email back to postfix, also using a tcp port.
5) Postfix then passes email to dovecot to store the mail somewhere
6) Dovecot uses sieve to decide where to put the email depending on
some parameters. For spam, it looks in the header for spamassassin's
spam tag. If it finds it, it puts it in the user's spam folder.
Otherwise, it goes to the inbox (actually to the next sieve test but
you know what I mean).
Spamassassin learns spam is spam (as in for its bayesian filter) when
it passes a preconfigured score threshold. Remember it scores emails
based on some search patterns and from its experience based on what is
in its spam/ham bayesian database, which is why they say you should
feed it with some intial spam and ham when first installing it.
Now, we also have two directories where users can put emails
mistakenly marked as spam and ham. Every night a script runs sa-learn
and goes through those two directories, marking spam as spam and ham
as ham.
>
>
> I've only been running postfix for a short time,
>
> after a disk failure forced me to re-install CentOS.
>
>
>
> Any elucidation gratefully received.
>
> --
>
> Timothy Murphy
>
> e-mail: gayleard /at/ eircom.net
>
> School of Mathematics, Trinity College, Dublin 2, Ireland
>
>
