policy banks question
Mark.Martinec+amavis at ijs.si
Fri Apr 15 01:45:36 CEST 2011
> I'm reading over:
> and I'm confused somewhat about the originating vs foreign regular
> expression bits for Postfix. It seems to me that both of these regular
> expression files are identical other than the port, so how is one email
> considered originating and another foreign? Is that something postfix
> "knows" based on the domain name?
> Basically, what I'm working on is setting domain disclaimers for
> "originating" emails (and eventually to do DKIM signing on originating
> emails as well). I don't need postfix to do any milter work, so I don't
> need the 10027 port. Right now I have ports 10024 and ports 10026 open via
> amavis, and 10026 is the originating policy bank. However, I am just
> missing how postfix "knows" an email is originating vs foreign based on
> those regular expressions.
We are talking about the following:
/^/ FILTER amavisfeed:[127.0.0.1]:10026
/^/ FILTER amavisfeed:[127.0.0.1]:10024
The magic is not in a regex (which matches everything which
reaches it), but in the order of rules in smtpd_sender_restrictions.
Remember that a FILTER in a matching access map just makes its
argument overlay the content_filter setting. The last FILTER
triggering has the final say (i.e. wins).
So the tag_as_originating.re places amavisfeed:[127.0.0.1]:10026
into a content_filter for everybody first.
Then smtpd_sender_restrictions proceeds to permit_mynetworks,
permit_sasl_authenticated and permit_tls_clientcerts. If any
of these three rules match, the search stops here and the
amavisfeed:[127.0.0.1]:10026 remains in content_filter.
If, however, none of the tree rules identifying local nets
or autheticated roaming users match, then the search reaches
the 'check_sender_access regexp:/etc/postfix/tag_as_foreign.re',
which overlays its cargo into a content_filter, which ends up
being amavisfeed:[127.0.0.1]:10024. This happens for any
inbound or nonauthenticated client - which is exactly what we
need (assuming amavisd has a policy bank with originating=>1
hanging on a TCP port 10026.
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