xref: /dflybsd-src/libexec/dma/dma.8 (revision 806fc0bc0359c1d53259f670a693baa4fb668ff9)

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.Dd January 17, 2023
.Dt DMA 8
.Os
.Sh NAME
.Nm dma
.Nd DragonFly Mail Agent
.Sh SYNOPSIS
.Nm
.Op Fl DiOt
.Op Fl A Ns Ar mode
.Op Fl b Ns Ar mode
.Op Fl f Ar sender
.Op Fl L Ar tag
.Op Fl o Ns Ar option
.Op Fl r Ar sender
.Op Fl q Ns Op Ar arg
.Op Ar recipient ...
.Sh DESCRIPTION
.Nm
is a small Mail Transport Agent (MTA), designed for home and office use.
It accepts mails from locally installed Mail User Agents (MUA) and
delivers the mails either locally or to a remote destination.
Remote delivery includes several features like TLS/SSL support and SMTP
authentication.
.Pp
.Nm
is not intended as a replacement for real, big MTAs like
.Xr sendmail 8
or
.Xr postfix 1 .
Consequently,
.Nm
does not listen on port 25 for incoming connections.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl A Ns Ar mode
.Fl \&Ac
acts as a compatibility option for sendmail.
.It Fl b Ns Ar mode
.Bl -tag -width indent
.It Fl bp
List all mails currently stored in the mail queue.
.It Fl bq
Queue the mail, but don't attempt to deliver it.
See also the
.Sq DEFER
config file setting below.
.El
.Pp
All other
.Ar mode Ns
s are ignored.
.It Fl D
Don't run in the background.
Useful for debugging.
.It Fl f Ar sender
Set sender address (envelope-from) to
.Ar sender .
This overrides the value of the
.Ev EMAIL
environment variable, but is overridden by the
.Sq MASQUERADE
config file setting.
.It Fl i
Ignore dots alone on lines by themselves in incoming messages.
This should be set if you are reading data from a file.
.It Fl L Ar tag
Set the identifier used in syslog messages to the supplied
.Ar tag .
This is a compatibility option for sendmail.
.It Fl O
This is a compatibility option for sendmail.
.It Fl o Ns Ar option
Specifying
.Fl oi
is synonymous to
.Fl i .
All other options are ignored.
.It Fl q Ns Op Ar arg
Process saved messages in the queue.
The argument is optional and ignored.
.It Fl r Ar sender
Same as
.Fl f .
.It Fl t
Obtain recipient addresses from the message header.
.Nm
will parse the
.Li To: ,
.Li Cc: ,
and
.Li Bcc:
headers.
The
.Li Bcc:
header will be removed independent of whether
.Fl t
is specified or not.
.El
.Sh CONFIGURATION
.Nm
can be configured with two config files:
.Pp
.Bl -bullet -compact
.It
auth.conf
.It
dma.conf
.El
.Pp
These two files are stored per default in
.Pa /etc/dma .
.Sh FILE FORMAT
Every file contains parameters of the form
.Sq name value .
Lines containing boolean values are set to
.Sq NO
if the line is commented and to
.Sq YES
if the line is uncommented.
Empty lines or lines beginning with a
.Sq #
are ignored.
Parameter names and their values are case sensitive.
.Sh PARAMETERS
.Ss auth.conf
SMTP authentication can be configured in
.Pa auth.conf .
Each line has the format
.Dq Li user|smarthost:password .
.Pp
.Nm
uses the recipient MTA hostname and finds the first entry in the auth.conf
file that matches the smarthost value or the hostname of the recipient
address.
It then uses the user and password to authenticate with the smarthost.
.Pp
Note, that the only authentication method supported is CRAM-MD5.
The receiving MTA must be configured to accept CRAM-MD5 authentication.
.Ss dma.conf
Most of the behaviour of
.Nm
can be configured in
.Pa dma.conf .
.Bl -tag -width 4n
.It Ic SMARTHOST Xo
(string, default=empty)
.Xc
If you want to send outgoing mails via a smarthost, set this variable to
your smarthosts address.
.It Ic PORT Xo
(numeric, default=25)
.Xc
Use this port to deliver remote emails.
Only useful together with the
.Sq SMARTHOST
option, because
.Nm
will deliver all mails to this port, regardless of whether a smarthost is set
or not.
.It Ic ALIASES Xo
(string, default=/etc/aliases)
.Xc
Path to the local aliases file.
Just stick with the default.
The aliases file is of the format
.Dl nam: dest1 dest2 ...
In this case, mails to
.Li nam
will instead be delivered to
.Li dest1
and
.Li dest2 ,
which in turn could be entries in
.Pa /etc/aliases .
The special name
.Ql *
can be used to create a catch-all alias, which gets used if no other
matching alias is found.
Use the catch-all alias only if you don't want any local mail to be
delivered.
.It Ic SPOOLDIR Xo
(string, default=/var/spool/dma)
.Xc
Path to
.Nm Ap s
spool directory.
Just stick with the default.
.It Ic AUTHPATH Xo
(string, default=not set)
.Xc
Path to the
.Sq auth.conf
file.
.It Ic SECURETRANSFER Xo
(boolean, default=commented)
.Xc
Uncomment if you want TLS/SSL secured transfer.
.It Ic STARTTLS Xo
(boolean, default=commented)
.Xc
Uncomment if you want to use STARTTLS.
Only useful together with
.Sq SECURETRANSFER .
.It Ic FINGERPRINT Xo
(string, default=empty)
.Xc
Pin the server certificate by specifying its SHA256 fingerprint.
Only makes sense if you use a smarthost.
.It Ic OPPORTUNISTIC_TLS Xo
(boolean, default=commented)
.Xc
Uncomment if you want to allow the STARTTLS negotiation to fail.
Most useful when
.Nm
is used without a smarthost, delivering remote messages directly to
the outside mail exchangers; in opportunistic TLS mode, the connection will
be encrypted if the remote server supports STARTTLS, but an unencrypted
delivery will still be made if the negotiation fails.
Only useful together with
.Sq SECURETRANSFER
and
.Sq STARTTLS .
.It Ic CERTFILE Xo
(string, default=empty)
.Xc
Path to your SSL certificate file.
.It Ic SECURE Xo
(boolean, default=commented)
.Xc
Uncomment this entry and change it to
.Sq INSECURE
to use plain text SMTP login over an insecure connection.
You have to rename this variable manually to prevent that you send your
password accidentally over an insecure connection.
.It Ic DEFER Xo
(boolean, default=commented)
.Xc
Uncomment if you want that
.Nm
defers your mail.
You have to flush your mail queue manually with the
.Fl q
option.
This option is handy if you are behind a dialup line.
.It Ic FULLBOUNCE Xo
(boolean, default=commented)
.Xc
Uncomment if you want the bounce message to include the complete original
message, not just the headers.
.It Ic MAILNAME Xo
(string, default=empty)
.Xc
The internet hostname
.Nm
uses to identify the host.
If not set or empty, the result of
.Xr gethostname 3
is used.
If
.Sq MAILNAME
is an absolute path to a file, the first line of this file will be used
as the hostname.
.It Ic MASQUERADE Xo
(string, default=empty)
.Xc
Masquerade the envelope-from addresses with this address/hostname.
Use this setting if mails are not accepted by destination mail servers
because your sender domain is invalid.
This setting overrides the
.Fl f
flag and the
.Ev EMAIL
environment variable.
.Pp
If
.Sq MASQUERADE
does not contain a
.Li @
sign, the string is interpreted as a host name.
For example, setting
.Sq MASQUERADE
to
.Ql john@
on host
.Ql hamlet
will send all mails as
.Ql john@hamlet ;
setting it to
.Ql percolator
will send all mails as
.So
.Sm off
.Va username @percolator
.Sm on
.Sc .
.It Ic NULLCLIENT Xo
(boolean, default=commented)
.Xc
Bypass aliases and local delivery, and instead forward all mails to
the defined
.Sq SMARTHOST .
.Sq NULLCLIENT
requires
.Sq SMARTHOST
to be set.
.El
.Ss Environment variables
The behavior of
.Nm
can be influenced by some environment variables.
.Bl -tag -width 4n
.It Ev EMAIL Xo
.Xc
Used to set the sender address (envelope-from).
Use a plain address, in the form of
.Li user@example.com .
This value will be overridden when the
.Sq MASQUERADE
config file setting or the
.Fl f
flag is used.
.El
.Sh SEE ALSO
.Xr forward 5 ,
.Xr mailwrapper 8 ,
.Xr sendmail 8
.Rs
.%A "J. B. Postel"
.%T "Simple Mail Transfer Protocol"
.%O RFC 821
.Re
.Rs
.%A "J. Myers"
.%T "SMTP Service Extension for Authentication"
.%O RFC 2554
.Re
.Rs
.%A "P. Hoffman"
.%T "SMTP Service Extension for Secure SMTP over TLS"
.%O RFC 2487
.Re
.Sh HISTORY
The
.Nm
utility first appeared in
.Dx 1.11 .
.Sh AUTHORS
.An -nosplit
.Nm
was written by
.An Matthias Schmidt Aq Mt matthias@dragonflybsd.org
and
.An Simon Schubert Aq Mt 2@0x2c.org .
.Sh CAVEATS
.Nm
does not currently support the
.Xr forward 5
feature.