courierfax - Send faxes via E-mail
The courierfax module (if enabled by the system administrator) sends E-mail
messages by fax. Addressing an E-mail message to the address 5558888@fax faxes
a printed copy of the message to the specified phone number.
The ability to send faxes may be restricted, or not available. The E-mail
message may be a MIME-formatted message. All attachments are concatenated and
sent together in a single fax transmission. courierfax only knows how to
handle certain kinds of attached. Obviously, trying to fax a voice .mp3
attaching is not going to work. courierfax knows how to handle plain text,
Postscript, and PDF MIME attachments. courierfax might also know what to do
with other kinds of attachment, depending on some optional software installed
by the system administrator. courierfax may also be able to read GIF, PNG, and
Color images are converted to black-and-white.
Images are faxed with one image per fax page (limiting image sizes to about
The message will be returned as undeliverable if courierfax doesn't know how to
handle a MIME attachment. If the first MIME section in the E-mail message is
plain text, the text appears on the fax cover page. The sender/recipient
information for the cover page is taken from the message's headers.
The default courierfax configuration tries to resend the fax for up to eight
hours, after which the message is returned as undeliverable. The message will
also be returned as undeliverable if the fax transmission is interrupted. The
return bounce will state how many pages were successfully transmitted.
"@fax" may also be followed by additional keywords that specify extra
Send a low-resolution fax.
Ignore any attachment types that courierfax
Send a cover page only. This is useful in
limited situations, with something like this in a
This .courier file faxes the contents of a message, sans any attachments,
immediately upon receipt in addition to saving the message in the
The sender will receive a fax transmission receipt if the sender requests an
ESMTP delivery status notification. This is the -N
sendmail -Nsuccess 5556666@fax <messagefile
When using other mail software, consult the mail software's documentation for
instructions on requesting ESMTP delivery status notifications.
courierfax configurations that are generated by the webadmin
North American environments usually restrict phone numbers to a standardized
ten-digit telephone number, so that the fax address is always <
@fax>, and courierfax silently performs any needed
conversion to dial the number (such as adding “1” or dropping
the local areacode).
It is also possible to reconfigure courierfax so that it accepts any telephone
string and dials it without any preprocessing. If so, the address may contain
any combination of digits, letters “A”, “B”,
“C”, and “D”, representing the four extra dialing
tones not normally accessible from most telephone keypads, the symbols
“*” and “#”, or the following characters:
Most faxmodems pause and wait for a secondary
dialtone, before dialing the rest of the number.
The dash is replaced by a comma in the dialing
string. A comma results in most faxmodems pausing for two or three seconds
before dialing the rest of the number. It is not possible to enter a comma
directly, because commas are used to separate multiple E-mail addresses. Use
dashes instead of commas in the dialing string. courierfax replaces all dashes
with commas before dialing the faxmodem.
Similarly, courierfax replaces all pluses with
“@” characters before dialing. An “@” characters
results in most faxmodems waiting for the line to be silent for five seconds
before dialing the rest of the number. It is not possible to enter a
“@” directly as part of the telephone number itself, for the
obvious reasons. Use pluses instead of “@”s in the dialing
string. courierfax replaces all pluses with “@” before dialing
The slightly arcane configuration file, /etc/courier/faxrc, sets up which
dialing strings are valid. The default configuration file contains judicious
comments that explain all the parameters, and what they do. The default
configuration file disables courierfax by rejecting all telephone numbers. The
file must be edited in accordance with the embedded instructions, in order to
is highly recommended. Upon demand, webadmin
install a suitable configuration file for the North American numbering plan,
that receives all telephone numbers as ten-digit numbers, and adds any
required long distance prefix, or removes the local area code, as appropriate.
will install a bare-bones configuration file that dials
any requested phone number, without any editing or transformation.
There is no good way to sleep until a modem lock is released, so we poll every