Category: Postfix

Configure spamass-milter

At first, you configure spamd.

spamd adds “[SPAM]” to spam mail’s subject by default. If you don’t like the behavior, edit /etc/mail/spamassassin/local.cf.

Before:

rewrite_header Subject [SPAM]

After:

# rewrite_header Subject [SPAM]

Add the following configuration to /etc/mail/spamassassin/local.cf. This configuration is for adding headers only if spam detected.

remove_header ham Status
remove_header ham Level

Start spamd on startup:

% sudo systemctl enable spamassassin

Start spamd:

% sudo systemctl start spamassassin

Here are spamass-milter’s configuration items:

Change /etc/sysconfig/spamass-milter:

Before:

#EXTRA_FLAGS="-m -r 15"

After:

EXTRA_FLAGS="-m -r 15"

Start spamass-milter on startup:

% sudo systemctl enable spamass-milter

Start spamass-milter:

% sudo systemctl start spamass-milter

Configure clamav-milter

Update ClamAV virus database and start clamd.

Edit /etc/freshclam.conf like the following. It comments out “Example”, changes “NotifyClamd” value and uncomments other items.

Before:

Example
#LogFacility LOG_MAIL
#NotifyClamd /path/to/clamd.conf

After:

#Example
LogFacility LOG_MAIL
NotifyClamd /etc/clamd.d/scan.conf

Run freshclam by hand at the first time:

% sudo freshclam

Configure clamd.

Edit /etc/clamd.d/scan.conf like the following. It comments out “Example” and uncomments other items:

Before:

Example
#LogFacility LOG_MAIL
#LocalSocket /run/clamd.scan/clamd.sock

After:

#Example
LogFacility LOG_MAIL
LocalSocket /run/clamd.scan/clamd.sock

Start clamd on startup:

% sudo systemctl enable [email protected]

Start clamd:

% sudo systemctl start [email protected]

Configure clamav-milter.

Edit /etc/mail/clamav-milter.conf like the following. It comments out “Example”, change “ClamdSocket” value and uncomments other items:

Before:

Example
#MilterSocket /run/clamav-milter/clamav-milter.socket
#MilterSocketMode 660
#ClamdSocket tcp:scanner.mydomain:7357
#LogFacility LOG_MAIL

After:

#Example
MilterSocket /run/clamav-milter/clamav-milter.socket
MilterSocketMode 660 
ClamdSocket unix:/run/clamd.scan/clamd.sock 
LogFacility LOG_MAIL

Add “clamilt” user to “clamscan” group to access clamd’s socket:

% sudo usermod -G clamscan -a clamilt

Start clamav-milter on startup:

% sudo systemctl enable clamav-milter

Start clamav-milter:

% sudo systemctl start clamav-milter

Configure milter-greylist

Change /etc/mail/greylist.conf for the following configurations:

Before:

socket "/run/milter-greylist/milter-greylist.sock"
# ...
racl whitelist default

After:

socket "/run/milter-greylist/milter-greylist.sock" 660
# ...
subnetmatch /24
greylist 10m
autowhite 1w
sm_macro "trusted_domain" "{trusted_domain}" "yes"
racl whitelist sm_macro "trusted_domain" spf pass
racl greylist sm_macro "trusted_domain" not spf pass
racl greylist default

Start milter-greylist on startup:

% sudo systemctl enable milter-greylist

Start milter-greylist:

% sudo systemctl start milter-greylist

Configure milter manager

Add “milter-manager” user to “clamilt” group to access clamav-milter’s socket:

% sudo usermod -G clamilt -a milter-manager

Add “milter-manager” user to “mail” group and “grmilter” group to access milter-greylist’s socket:

% sudo usermod -G mail -a milter-manager
% sudo usermod -G grmilter -a milter-manager

Add “milter-manager” user to “postfix”” group to access spamass-milter’s socket:

% sudo usermod -G postfix -a milter-manager

milter manager detects milters that installed in system. You can confirm spamass-milter, clamav-milter and milter-greylist are detected:

% sudo /usr/sbin/milter-manager -u milter-manager -g milter-manager --show-config

The following output shows milters are detected:

...
define_milter("milter-greylist") do |milter|
  milter.connection_spec = "unix:/run/milter-greylist/milter-greylist.sock"
  ...
  milter.enabled = true
  ...
end
...
define_milter("clamav-milter") do |milter|
  milter.connection_spec = "unix:/var/run/clamav-milter/clamav-milter.socket"
  ...
  milter.enabled = true
  ...
end
...
define_milter("spamass-milter") do |milter|
  milter.connection_spec = "unix:/run/spamass-milter/postfix/sock"
  ...
  milter.enabled = true
  ...
end
...

You should confirm that milter’s name, socket path and “enabled = true”. If the values are unexpected, you need to change /etc/milter-manager/milter-manager.local.conf. See Configuration for details of milter-manager.local.conf.

But if we can, we want to use milter manager without editing miter-manager.local.conf. If you report your environment to the milter manager project, the milter manager project may improve detect method.

milter manager’s configuration is finished.

Start to milter manager on startup:

% sudo systemctl enable milter-manager

Start to milter manager:

% sudo systemctl start milter-manager

milter-test-server is usuful to confirm milter manager was ran:

% sudo -u milter-manager milter-test-server -s unix:/var/run/milter-manager/milter-manager.sock

Here is a sample success output:

status: accept
elapsed-time: 0.128 seconds

If milter manager fails to run, the following message will be shown:

Failed to connect to unix:/var/run/milter-manager/milter-manager.sock

In this case, you can use log to solve the problem. milter manager is verbosily if –verbose option is specified. milter manager outputs logs to standard output if milter manager isn’t daemon process.

You can add the following configuration to /etc/sysconfig/milter-manager to output verbose log to standard output:

OPTION_ARGS="--verbose --no-daemon"

Restart milter manager:

% sudo systemctl restart milter-manager

Some logs are output if there is a problem. Running milter manager can be exitted by Ctrl+c.

OPTION_ARGS configuration in /etc/sysconfig/milter-manager should be commented out after the problem is solved to run milter manager as daemon process. And you should restart milter manager.

Configure Postfix

Enables Postfix:

% sudo systemctl enable postfix
% sudo systemctl start postfix

Configure Postfix for milters. Append following lines to /etc/postfix/main.cf:

milter_protocol = 6
milter_default_action = accept
milter_mail_macros = {auth_author} {auth_type} {auth_authen}

For details for each lines.

Register milter manager to Postfix. It’s important that spamass-milter, clamav-milter and milter-greylist aren’t needed to be registered because they are used via milter manager.

Append following lines to /etc/postfix/main.cf:

smtpd_milters = unix:/var/run/milter-manager/milter-manager.sock

Reload Postfix’s configuration.

% sudo systemctl reload postfix

milter manager logs to syslog. If milter manager works well, some logs can be shown in /var/log/maillog. You need to send a test mail for confirming.