An open source eFax server solution written in Python that allows sending and receiving faxes via integration with Asterisk PBX, with support for multiple accounts each with their own users and details.

🔴 IMPORTANT: This project is still in BETA. It is a highly functional and working beta but you should expect some bugs. Please report all issues using the Issues tab.

About & Why

Fax... in 2023.... really? Yes, really. While nowhere near as prevalent as they once were, fax machines are still used in 2023 due to faxes continued prevalence within key industries and some countries.

While there are a range of commercial solutions available in the form of fax servers and fax services , most open source implementations for fax were almost a decade old (if not older) and used outdated practices and outdated technology.

NexeFax is a complete reimplementation of eFax using current practices the latest versions of software, built fully with the same open source spirit as other

Some of the key features of NexeFax include:

• Multiple Fax Accounts
• Web UI interface to easily send faxes
• Each Fax Account can have multiple users for web UI access
• Inbuilt FastAGI server for Asterisk
• Very low memory footprint (~30Mb)

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Compose

How it works

NexeFax has 3 main components, it's inbuilt FastAGI server which receives events from Asterisk (such as when a Fax is received or after one is sent), it's inbuilt HTTP server which enables a web UI for users to send faxes, and it's inbuilt eFax server which handles the processing of PDF and TIFF files.

Recieving Faxes

Faxes are received by Asterisk and stored as a TIFF file. An AGI request is then made to NexeFax to start processing all received faxes. NexeFax parses the directory where Asterisk has stored the TIFF Fax files, converts them to PDF, processes and emails them accordingly.

Sending Faxes

Users send faxes using the web UI. The request is received by the inbuilt HTTP server which passes it along to the eFax server. The eFax server converts the PDF file to a TIFF file and creates an Asterisk call file using the dedicated send extension in the [nexefax] dialplan context.

Installation

NexeFax is simple to install and run but you must read these installation instructions in full to understand how it works.

Installing Dependencies

NexeFax depends on the following:

• Asterisk 16+ PBX
• res_fax (for Asterisk)
• Python 3.10+
• python_bcrypt (needed for dealing with user authentication)
• Imagemagick (to convert Fax TIFF files to PDF files)
• Ghostscript (to convert PDF files to Fax TIFF files)
• apache2-utils (needed for htpasswd to interact with auth files)

On a Debian/Ubuntu based Linux system run the following:

apt-get install python3 python3-bcrypt imagemagick ghostscript apache2-utils

Note that this does not deal with the installation of Asterisk or res_fax. These must be installed separately.

Installing NexeFax Server

Extract the NexeFax server files to /usr/lib/nexefax.

cd /tmp
wget https://github.com/NexusPolytech/NexeFax/archive/refs/tags/v0.0.1.tar.gz
tar -xf v0.0.1.tar.gz
cp -r /tmp/NexeFax-0.0.1/ /usr/lib/nexefax

Integration with Asterisk Dialplan

Add the [nexefax] context from the dialplans/asterisk/extensions.conf file into your Asterisk dialplan.

When you want to receive a fax, your Dialplan must go to the receive extension of the [nexefax] context. You need to pass the Fax Account ID as the first argument.

In the below example, this is the fax extension for our context for ACME Corporation, which has been setup with the NexeFax account ID ACME.

exten => fax,1,Gosub(nexefax,receive,1(ACME))

Running & Controlling NexeFax Server

NexeFax is a standalone Python server and should be run as a daemon or service.

Using systemd for Debian/Ubuntu

On Debian/Ubuntu based systems, you can run and control NexeFax using a systemd service file.

cp /usr/lib/nexefax/control/systemd/nexefax.service /etc/systemd/system/nexefax.service
systemctl daemon-reload

Once the service file has been copied and the systemctl has been reloaded, you can run NexeFax using:

systemctl start nexefax
or
service nexefax start

Using a HTTPS Reverse Proxy

The inbuilt HTTP server for NexeFax web UI does not support HTTPS. It is best practice to ensure that you use a reverse proxy server, such as Nginx or Apache, to securely provide NexeFax's web UI on a public facing interface.

A sample server configuration file for Nginx is included in the /usr/lib/nexefax/http-samples directory.

Configuring NexeFax

NexeFax is configured with three types of files stored in /etc/nexefax:

1. config.conf: This is the main configuration files that controls NexeFax.

2. accounts.conf: This is the accounts file the creates the fax accounts that can send and receive faxes.

3. auth files: These are htpasswd files that must be created for each account that has been configured which contain the username and passwords for the users who can sign in and send faxes from that account.

Create the accounts.conf and config.conf files in /etc/nexefax. You can copy samples of these files from the conf-samples folder.

mkdir /etc/nexefax/
cp -r /usr/lib/nexefax/conf-samples/* /etc/nexefax/

config.conf

The following options can be configured in config.conf and effect all of NexeFax.

Section	Option	Purpose	Required	Options	Default
general	tx_channel	The Asterisk channel that will originated to send a fax. This must contain the string ${TO} which will be replaced with the recipient fax number.	Yes
general	rx_dir	The directory that recieved fax TIFF files are stored in.			/var/spool/asterisk/tmp
general	ast_call_dir	The directory that Asterisk call files will be placed.			/var/spool/asterisk/outgoing
general	tmp_dir	The tmp directory for NexeFax temp files.			/tmp/nexefax
general	ast_context	The Asterisk dialplan context for NexeFax.			nexefax
general	tx_max_retries	Number of time Asterisk should attempt to make the call before failing attempt.			5
general	tx_retry_time	Number of seconds Asterisk should wait between retries.			300
general	tx_wait_time	Number of seconds Asterisk should wait for an answer.			30
general	tx_faxopt_ecm	Set the Asterisk FAXOPT item 'ecm'.			Yes
general	tx_faxopt_modem	Set the Asterisk FAXOPT item 'modem'.			v17,v27,v29
general	tx_faxopt_faxdetect	Set the Asterisk FAXOPT item 'faxdetect'.
general	tx_faxopt_minrate	Set the Asterisk FAXOPT item 'minrate'.			4800
general	tx_faxopt_maxrate	Set the Asterisk FAXOPT item 'maxrate'.			14400
general	tx_faxopt_t38timeout	Set the Asterisk FAXOPT item 't38timeout'.			5000
general	tx_faxopt_negboth	Set the Asterisk FAXOPT item 'negotiate_both'.
logging	file	Set the NexeFax log file.			/var/log/nexefax/info.log
logging	debug	Enable debug mode.		Yes or No	/var/log/nexefax/info.log
server	bind	The IP address to bind on.		0.0.0.0 for every IP address or a specific IP address	0.0.0.0
server	port_fagi	The port the FastAGI server should listen on.			4573
server	port_http	The port the HTTP server should listen on.			3298
server	web_session_length	How long in seconds an authenticated web users session should last.			86400
email	method	How email should be sent.		sendmail or smtp	sendmail
email	smtp_mode	If [email] method is smtp, the connection mode for the SMTP connection.		tls for STARTTLS, ssl for SSL, leave blank for nothing
email	smtp_port	If [email] method is smtp, the port for the SMTP connection.			25
email	smtp_auth	If [email] method is smtp, if authentication is needed for this connection.		Yes or No
email	smtp_host	If [email] method is smtp, the SMTP host to connect to.		IP or FQDN	127.0.0.1
email	smtp_auth_user	If [email] smtp_auth is Yes, the auth user.
email	smtp_auth_pass	If [email] smtp_auth is Yes, the auth password.
email	from_name	The name emails should be sent from.			NexeFax
email	from_email	The address emails should be sent from.			nexefax@your local host name
email	subject	The subject that should be used for new faxes recieved.			nexefax@your local host name

accounts.conf

The section name for an account is it's account ID and is used to identify that account and to sign in to that account in the Web UI.

[ACME]
info_name=ACME Corporation
info_fax=202 555 0154
info_phone=202 555 0103
info_email=contact@acme.corp
info_web=www.acme.corp

In the above example, the account ID is ACME

The following options can be configured for each account in accounts.conf and effect that specific account.

Option	Purpose	Required	Options	Default
rx_email_to	The email address(es) that Faxes will be sent to.	Yes	Can be a single email address of multiple email addresses seperated by a comma (,)
rx_email_cc	The email address(es) that Faxes will be CC'd to.		Can be a single email address of multiple email addresses seperated by a comma (,)
rx_email_subject	The subject for new eFax emails.			The default set in the [email] subject option in config.ini
tx_number	The number (inclding country and area code) faxes will be sent from, with no symbols or letters.	Yes
tx_name	The name of the entity sending the faxes.
tx_notify_success	Send an email when a fax from this account was sent successfully.		True or False	False
tx_notify_failure	Send an email when a fax from this account failed to send.		True or False	True
tx_channel	Override the TX channel for this account.

The following options can be configured to provide information for the sending entity. They are not used yet but will be used in future versions.

Option	Purpose
info_name	Information about the sending entity: Name
info_fax	Information about the sending entity: Fax Number
info_phone	Information about the sending entity: Phone
info_email	Information about the sending entity: Email Address
info_web	Information about the sending entity: Website

Auth Files

Auth files are htpasswd files which are stored inside /etc/nexefax/auth. They are used to allow access to the web UI by the HTTP server.

You must setup an auth file for each account you have created in accounts.conf.

In the below example we will be creating a user named bob.smith within the ACME account auth file.

NOTE: You must ensure that bcrypt is used by passing the -B argument to htpasswd.

htpasswd -B -c /etc/nexefax/auth/ACME bob.smith

New password: MyStrongPassword123
Re-type new password: MyStrongPassword123
Adding password for user bob.smith

You can use the exact same command as above with an existing user to change their password.