README revision 90807 
1# $FreeBSD: head/etc/mail/README 90807 2002-02-17 22:14:29Z gshapiro $
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 false,
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 turned off, 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.  Be default, it simply runs the
38client mail queue every 30 minutes.  It's 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.
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