--------------------------------------------------------------
  Integrating spamass-milter into your sendmail installation
--------------------------------------------------------------

You will need to edit /etc/mail/sendmail.mc and add an
INPUT_MAIL_FILTER line that connects to the spamass-milter socket.

By default the spamass-milter socket is
/var/run/spamass/spamass.sock; so your INPUT_MAIL_FILTER should look
something like:

 # spamassassin settings
 INPUT_MAIL_FILTER(`spamassassin',
         `S=local:/var/run/spamass/spamass.sock, F=,
         T=S:4m;R:4m;E:10m')dnl
 define(`confMILTER_MACROS_CONNECT',`t, b, j, _, {daemon_name}, {if_name}, {if_addr}')dnl
 define(`confMILTER_MACROS_HELO',`s, {tls_version}, {cipher}, {cipher_bits}, {cert_subject}, {cert_issuer}')dnl
 define(`confMILTER_MACROS_ENVRCPT',`b, i, j, r, v, Z, _')dnl

Briefly, the F=, tells sendmail to just pass the connection through if
the milter fails. This is most likely the setting you want. If you
want to temporarily fail a connection, you can set F=T. You almost
definitely don't want to reject connections, but if necessary, you can
do that by setting F=R.

You may also need to adjust these timeout settings, as spamd can be
sluggish on a slow machine. S is the timeout for sending information
from the MTA to a filter. R is the timeout for reading a reply from
the filter. E is the overall timeout between sending end-of-message to
filter and waiting for the final acknowledgment.

The settings above seem to work well on a Celeron 466 that receives
around 1000 emails an hour. You may wish to adjust them according to
your needs.

See http://www.sendmail.com/partner/resources/development/milter_api/installation.html
and http://www.sendmail.org/m4/adding_mailfilters.html#INPUT_MAIL_FILTER
for more information on milters.

If you are using the alias expansion method, -x, you will need to add
spamass-milter to the smmsp group using:

 adduser spamass-milter smmsp;

This does not need to be done unless you are using alias expansion.

--------------------------------------------------------------
  Integrating spamass-milter into your postfix installation
--------------------------------------------------------------

You need to edit /etc/postfix/main.cf and configure smptpd_milters so
that postfix connects to the spamass-milter socket. Something like:

  # spamass-milter configuration
  smtpd_milters = unix:/var/spool/postfix/spamass/spamass.sock

should work. Note, however, if you're using a chrooted version of
postfix, you'll need the local path to the socket inside of the
chroot. In recent versions of Debian the following should work:

  # spamass-milter configuration
  smtpd_milters = unix:/spamass/spamass.sock
  # milter macros useful for spamass-milter
  milter_connect_macros = j {daemon_name} v {if_name} _
  milter_data_macros = j i {auth_type} {daemon_name} v {if_name} _
  milter_rcpt_macros = j {auth_type} {daemon_name} v {if_name} _

See http://www.postfix.org/MILTER_README.html or
/usr/share/doc/postfix/MILTER_README.gz (in postfix-doc) for
information on how to set tempfail and the various timeouts that the
sendmail configuration above uses.

The defaults for spamass-milter adjust themselves so that no
configuration in /etc/default/spamass-milter should be required.
[However, if you are not doing so, see below.]

-------------------------------------------------------------
  Adjusting how spamass-milter is started
-------------------------------------------------------------

You can adjust how spamass-milter starts, and the options it calls
spamc with by adjusting /etc/default/spamass-milter. OPTIONS is passed
directly to spamass-milter by /etc/init.d/spamass-milter. [Refer to
spamass-milter(1) for details.]

Other settings which may be of use:

SOCKET sets the location of the socket; defaults to
/var/run/spamass/spamass.sock unless you are running postfix, where it
is set to /var/spool/postfix/spamass/spamass.sock.

SOCKETOWNER is the owner of the socket, which defaults to root:root or
postfix:postfix if you're running postfix.

SOCKETMODE is the mode of the socket, which defaults to 0600 or 0660
if you're running postfix.

RUNAS controls the user which spamass-milter runs as; defaults to
spamass-milter.

If you want to use an inet socket for spamass-milter (like inet:9999
or inet:9999@127.0.0.1), then you'll need to make the following
configuration changes in /etc/default/spamass-milter:

SOCKET="inet:9999@127.0.0.1"
SOCKETMODE=""
SOCKETOWNER=""

-------------------------------------------------------------
Debugging spamass-milter
-------------------------------------------------------------

As spamass-milter is still undergoing development, you may see bugs
from time to time.

If spamass-milter is segfaulting (SEGV or SIG 11) please build a
debugging version of the spamass-milter package and install it:

mkdir temp;
cd temp;
apt-get source spamass-milter;
apt-get build-dep spamass-milter;
cd spamass-milter-*;
DEB_BUILD_OPTIONS='nostrip' CXXFLAGS='-O0 -g' fakeroot debian/rules clean binary;
dpkg -i spamass-milter*.deb;

Then turn on coredumps (ulimit -c unlimited), and start spamass-milter
as usual (/etc/init.d/spamass-milter start).

When spamass-milter cores, run gdb on the core, ala:
gdb /usr/sbin/spamass-milter /foo/corefile.pid
thread apply all where
bt
q

and send the results along with your bug report using reportbug.

 -- Don Armstrong <don@debian.org>, Thu, 10 May 2018 11:15:25 -0700
