1# $FreeBSD$ 2 3 Sendmail Processes 4 5As of sendmail 8.12, in order to improve security, the sendmail binary no 6longer needs to be set-user-ID root. Instead, a set-group-ID binary 7accepts command line mail and relays it to a full mail transfer agent via 8SMTP. A group writable client mail queue (/var/spool/client-mqueue/ by 9default) holds the mail if an MTA can not be contacted. 10 11To accomplish this, under the default setup, an MTA must be listening on 12localhost port 25. If the rc.conf sendmail_enable option is set to "NO", 13a sendmail daemon will still be started and bound only to the localhost 14interface in order to accept command line submitted mail. If this is not 15a desirable solution, it can be disabled using the sendmail_submit_enable 16rc.conf option. However, if both sendmail_enable and sendmail_submit_enable 17are set to "NO", you must do one of two things for command line submitted 18mail: 19 201. Designate an alternative MTA for the submission agent to contact 21 by altering /etc/mail/submit.mc and using 'make submit.cf' in 22 /etc/mail/. Change the FEATURE(msp) line to FEATURE(msp, hostname) 23 where hostname is the fully qualified hostname of the alternative MTA. 24 25Or: 26 272. Return to using a set-user-ID root sendmail binary by changing the 28 ownership and permissions on the sendmail binary and removing the 29 /etc/mail/submit.cf file: 30 chown root /usr/libexec/sendmail/sendmail 31 chmod 4755 /usr/libexec/sendmail/sendmail 32 rm /etc/mail/submit.cf 33 If you install from source, set the SENDMAIL_SET_USER_ID flag in 34 /etc/make.conf. 35 36Also, as of 8.12, a new queue-running daemon is started to make sure mail 37doesn't remain in the client mail queue. By default, it simply runs the 38client mail queue every 30 minutes. Its behavior can be adjusted by setting 39the sendmail_msp_queue_enable and sendmail_msp_queue_flags rc.conf options. 40 41 42 Filtering out SPAM from your site 43 44Sendmail now includes excellent tools to block spam. These tools are 45available as FEATUREs that you can add to your site's .mc file. Proper use 46of these FEATUREs will prevent spammer from using your site as a relay as 47well as significantly decrease the amount of spam that arrives at your 48site. No set of anti-spam tools will block all spam without blocking some 49portion of legitimate mail as well. Therefore, these FEATUREs are designed 50to prevent as much spam as possible without blocking legitimate mail. 51 52These tools are discussed in /usr/share/sendmail/cf/README. Read the 53section entitled "ANTI-SPAM CONFIGURATION CONTROL". Example usage and 54additional tools can be found in /usr/share/sendmail/cf/cf/knecht.mc. 55 56