1# $FreeBSD: src/etc/mail/README,v 1.8.2.6 2002/05/22 17:01:32 gshapiro Exp $ 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/clientmqueue/ 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 (note that this 15does not work inside jail(2) systems as jails do not allow binding to 16just the localhost interface). If this is not a desirable solution, it 17can be disabled using the sendmail_submit_enable rc.conf option. However, 18if both sendmail_enable and sendmail_submit_enable are set to "NO", you 19must do the following for command line submitted mail: 20 21 Designate an alternative host for the submission agent to contact 22 by creating /etc/mail/<hostname>.submit.mc or using an alternate .mc 23 file and setting SENDMAIL_SUBMIT_MC in /etc/make.conf. Do not edit 24 dragonfly.submit.mc directly as it will be overwritten eventually, but 25 it certainly can be copied to be used as a template. 26 27 Type 'make install-submit-cf' in /etc/mail/ to generate the submit.cf 28 file. Change the FEATURE(msp) line to FEATURE(msp, hostname) where 29 hostname is the fully qualified hostname of the alternative host. 30 31Also, as of 8.12, a new queue-running daemon is started to make sure mail 32doesn't remain in the client mail queue. By default, it simply runs the 33client mail queue every 30 minutes. Its behavior can be adjusted by setting 34the sendmail_msp_queue_enable and sendmail_msp_queue_flags rc.conf options. 35 36 37 Filtering out SPAM from your site 38 39Sendmail now includes excellent tools to block spam. These tools are 40available as FEATUREs that you can add to your site's .mc file. Proper use 41of these FEATUREs will prevent spammer from using your site as a relay as 42well as significantly decrease the amount of spam that arrives at your 43site. No set of anti-spam tools will block all spam without blocking some 44portion of legitimate mail as well. Therefore, these FEATUREs are designed 45to prevent as much spam as possible without blocking legitimate mail. 46 47These tools are discussed in /usr/local/share/sendmail/cf/README. Read the 48section entitled "ANTI-SPAM CONFIGURATION CONTROL". Example usage and 49additional tools can be found in /usr/local/share/sendmail/cf/cf/knecht.mc. 50