## Determine which MTA is being used on the system ##

[Author](authors.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

[Reviewer](technical_reviewers.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

[Reviewer](technical_reviewers.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

----



### Concept ###

Recognize the role of the MTA, recognize
which MTA(s) are available during each BSD's operating system install
routine and which configuration file indicates the MTA(((MTA)))
in use on the system. Recognize the difference
between the mbox(((mbox))) or maildir(((maildir))) mail destination
file format type.


### Introduction ###

By default, the BSD systems have mail transfer agent (MTA) enabled for at least handling mails sent from the local machine.

<!--
openbsd
sendmail_flags="-L sm-mta -C/etc/mail/localhost.cf -bd -q30m"
-->

FreeBSD, OpenBSD, and DragonFly include Sendmail in their base installs.
NetBSD includes Postfix. (TODO: FOOTNOTE: Older versions of NetBSD included both Sendmail and Postfix.)

Third-party MTA alternatives or sendmail replacements are available through the package collections,
such as Exim, Qmail (not included in OpenBSD's ports), Postfix and many others.

Selecting the MTA can be done by configuring the mailer.conf configuration used by the mailwrapper tool.
The BSD's default /usr/sbin/sendmail (TODO: what about /usr/lib/sendmail) is really a symlink to /usr/sbin/mailwrapper.
This uses /etc/mail/mailer.conf (or /etc/mailer.conf on NetBSD) to define common replacement programs.

TODO: for example

TODO: show how can be tested

TODO: note that this BSDA doesn't teach how to configure a mail server, but
TODO: briefly cover how to turn on and off and how to disable at boot and where logs are at
TODO: point to other sections for details


### Examples ###

### Practice Exercises ###

1. What is your default sendmail?

### More information ###

mailer.conf(5)


