Q9201: On FreeBSD, /usr/sbin/sendmail is a symbolic link to /usr/sbin/mailwrapper; it doesn't contain the Sendmail binary. How should I replace Sendmail with Exim on FreeBSD?
A9201: There is a file called /etc/mail/mailer.conf which selects what to run for various MTA calls. Instead of changing /usr/sbin/sendmail, you should edit this file instead, to read something like this:
sendmail /usr/exim/bin/exim send-mail /usr/exim/bin/exim mailq /usr/exim/bin/exim -bp newaliases /usr/bin/true
You probably also need to edit /etc/periodic.conf; see Q9202.
Q9202: A script that FreeBSD runs nightly uses mailq with the -Ac parameter. Why doesn't Exim recognize this?
A9202: -Ac is a Sendmail option that requests that mailq ``Show the mail submission queue specified in /etc/mail/submit.cf instead of the MTA queue specified in /etc/mail/sendmail.cf''. Exim doesn't have the concept of a “submission queue”. You can disable this feature of the nightly script by adding the line
daily_status_include_submit_mailq="NO" # No separate 'submit' queue
to the file /etc/periodic.conf.
Q9203: How can I use Exim for authenticated SMTP using Cyrus on FreeBSD?
A9203: This web page may help: http://www.munk.nu/exim/exim-freebsd-asmtp.php.