Applies to VoipNow 3 and higher!

This article explains the fax mechanism in VoipNow, more precisely the sending of fax messages as attachments to emails, also known as the email2fax feature.

Sending a fax message

VoipNow's email2fax feature allows you to send fax messages by attaching the fax content as a .pdf, .jpg or .tiff file to an email message, which is then sent to a special faxing email address on the server.

Before explaining how this actually happens, you should know that only Phone terminal extensions support the email2fax feature. After receiving the fax message as attachment to an email, the server asks the sender for approval. When confirmed, it converts the attachment into a suitable fax format and sends it to the number(s) specified in the email subject.

The sender's address is used by the system to verify the destination extension for the email-generated fax. In order to be able to send faxes using the email2fax feature, the sender's email must be added to one of the extensions in the system. For more details, check the How to Enable Faxing for an Extension section.

Please note that only one extension can send faxes to that sender, so you cannot add the sender's email address on several extensions.

Enabling fax features server-wide 

To enable the email2fax feature, go to Unified Communications → Zero Priority → Fax tab.

The Fax Preferences available are:

Enabling faxing for an extension

Choose the extension you want to enable the fax feature for, click the Phone terminal setup icon and fill in the options available in the Fax Center section:

You may leave the other options with their default values. Such options are used only when the extension receives faxes.

Changing the standard messages sent by the server

The email notification sent by the server to the customer for fax approval can be globally customized.

To do this, go to the Unified Communications → Email templates page. The following templates can be customized from the Unified Communications Email Templates section:

Templates can be further customized on both service provider and organization levels by clicking their corresponding Email templates icon.

All the email templates use variables to automatically insert strings such as the phone number. The variables are displayed in the [VARIABLE_NAME] form. For more information about the available variables, consult the Email Templates section from the online help.

Canceling an attempt to resend a fax

In the Extension Management page, click the Sent faxes button. The system keeps a log of all fax messages queued for the current extension.

The section is organized as follows:

Sending a fax email

To send a fax email, you need to create an email with the following mandatory elements:

If you want the best results with the PDF files, it's recommended to create them using embedded fonts.


Check for issues in maillog

Fax emails get processed by the Postfix mail server. Postfix keeps a log of its activity in the /var/log/maillog logfile. To watch the maillog, run the following command:

tail -f /var/log/maillog

Check if emails reach the server 

If a client's email has reached the server, you should be able to see it in the maillog. We recommend that you look for an entry similar to this one:

DATE TIME SERVER_HOSTNAME postfix/smtpd[21802]: E9324D318D06: client=HOSTNAME[IP_ADDRESS]

This means that the client's machine has connected to the server. Therefore you're not dealing with a connection-related issue. Then the destination address is checked and, if it turns out invalid (it should be the same as the one set up on the server to receive fax messages), the email is dropped. If that's the case, the system will send you a notification. 

Check if faxes get processed

If the email has reached the server and its destination is valid, it gets sent through the procmail utility. The attachment is processed with the help of the faxprocess utility.

faxprocess logs its activity in /var/log/maillog

If the email reaches the server and gets validated by Postfix reaching faxprocess, yet the fax does not get sent, then ensure that:

Location of fax files (based on the stage of approval)

The faxprocess script uses two directories:

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