[Spamassassin Wiki] Update of "IntegratePosfixViaSpampd" by ThomasD

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The following page has been changed by ThomasD:
http://wiki.apache.org/spamassassin/IntegratePosfixViaSpampd

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= Integrating SpamAssassin into Postfix using spampd =
Let's try the hard way to secure our mailsystems.
Not as convienient as using spamd and spamc is the aproach
menthioned in the postfix FilterReadme. Some guys at
http://www.WorldDesign.com/index.cfm/rd/mta/spampd.htm
have puplished a spamd-replacement that is working as a SMTP-Proxy.
The advantage compared to spamd/spamc is, that problems with either
PEARL, Spamassassin and it's configuration doesn't lead in loosing mail.
The SMTP-proxy is designed to reject Mail in case of not recoverable faults.

It can easily be integrated as an "content_filter" in postfix.
The knack is, that mail that is classified as spam is forwarded
to users, where the filter of their local eMail-client should detect
the spamstatus. Goal should be, to forward spam to a special
user named "spamking". This could be done by using a alias-map
for all users that like their spam removed.
The solution described here is for a Mail-server with a limited number
of users with varying knowledge. All users  are "local", meaning they get
their mail via POP/IMAP from the mailserver.

First of all make shure, your postfix-server is heathy. The things
we'll do are somewhat confusing the simple world of Postfix.

At the beginning, edit /etc/postfix/master.cf:
{{{
# ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (50)
# ==========================================================================
...
smtp      inet  n       -       n       -       -       smtpd
...
scan               unix    -        -        n        -        10        smtp
localhost:10026    inet    n        -        n        -        10        smtpd
        -o content_filter=
        -o local_recipient_maps=
        -o relay_recipient_maps=
        -o myhostname=filter.mynetwork.local
        -o smtpd_helo_restrictions=
        -o smtpd_client_restrictions=
        -o smtpd_sender_restrictions=
        -o smtpd_recipient_restrictions=permit_mynetworks,reject
        -o mynetworks=127.0.0.0/8
spamtnsp	  unix	-	n	n	-	-	local
        -o alias_maps=hash:/etc/postfix/spamalias
}}}

second, edit /etc/postfix/main.cf:
{{{
content_filter =scan:[127.0.0.1]:10025
header_checks = regexp:/etc/postfix/spamheadercheck
}}}

The servicename "scan" is free and refers to the entry content_filter in main.cf.
Scan defines, that smtp should be used.
The scanpd-daemon is listening to 10025 and will deliver to localhost:10026.
The transport "localhost:10026" defines an smtpd-server, with options slightly
different to the main smtp server. Especialy the "content_filter=" is needed.

The file "spamheadercheck" mentioned in main.cf consist of one line:
{{{
/^X-Spam-Status: Yes/ FILTER spamtnsp:local
}}}
The regular expression searches every mail (including that, coming from the local net!)
for the header "X-Spam-Status: Yes", whitch is placed by spamassassin in case of spam.
The spam will be passed to the local transport spamtnsp. defined in master.cf.
The spamtnsp has the option alias_maps pointing to "spamalias".
In spamalias every user, witch doesn't want his spam delivered has an alias:
{{{
user1:  spamking
user2:  spamking
...
}}}
The menthioned user spamking must have a home-directory. Spamking
can be used as user for the sitewide bayes-filter and as daemonuser
for spampd.

After thinking about we have done, we can start the spampd and postfix
by calling
{{{
spampd --port=10025 --relayhost=127.0.0.1:10026 --user=spamking --tagall
rcpostfix reload
}}}
A test should be made with "telnet 127.0.0.1 10025". The Postfix-SMTP should
be accessible via the Proxy.

Next step is ripping the rc-script spamassassin in order to start spampd. Perhaps
someone is able to change spampd in the way that it can be started by postfix
itself via master.cf.