Howto:Configure Faxserver to accept SMTP without authentication

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This article is obsolete. The function SMTP without authentication is included in the Fax server application version V10 SR13 or later. See also Authorized Hosts in Reference10:Concept Faxserver.


Applies To

This information applies to

  • innovaphone Faxserver (till version 10 SR12)

Security Alert

The innovaphone Faxserver accepts incoming SMTP connections only with authentication due to security reasons. The solution described here is not recommended by innovaphone.

If this setting is changed as described in this article, it is possible to send fax messages using your fax server to any destination for anybody, who can reach the Faxserver via IP.

Use an SMTP-Client on Users PC

Instead, you may consider to set-up your user PCs so that they send outgoing faxes directly to the fax server via authenticated SMTP.

Usually E-Mail client applications, like Mozilla Thunderbird or Microsoft Outlook, are able to send E-Mails via SMTP with authentication. In Thunderbird it is possible to add an additional SMTP Server, and in Outlook an additional Mail Account pointing to the Faxserver as SMTP Server.

More Information

Problem Details

In cases it is not possible to configure outgoing SMTP authentication on the E-Mail server, following possible solutions are available:

  • Use a local E-Mail client like Mozilla Thunderbird or Microsoft Outlook to send Fax E-Mails directly to the Faxserver using SMTP Authentication
  • In case your Faxserver is operating in a secured network, it is possible to change settings on the Linux AP hosting the Faxserver in order no SMTP authentication is required for inbound connections.

Configuration with disabled Authentication

At the moment only manual change of the configuration files on Linux is possible to disable SMTP Authentication:

For the first you have to put the IP address of the SMTP server under /etc/postfix/

mynetworks = [::ffff:]/104 [::1]/128

E.g. at the end of the line is my SMTP server.

The second file to change is /var/mail/vhosts/catchall.faxserver/.dovecot.sieve

The original file contains:

require ["variables"];

if header :matches "Received" "*(Authenticated sender: *)*" {
        redirect "${2}@redirected.faxserver"; stop;
} else {

The line with "discard;" must be changed to "redirect "default@redirected.faxserver"; stop;", like this:

require ["variables"];

if header :matches "Received" "*(Authenticated sender: *)*" {
        redirect "${2}@redirected.faxserver"; stop;
} else {
        redirect "default@redirected.faxserver"; stop;

It is important to match "default" with the User of the Mail Configuration of the Faxserver. So the Name of the SMTP User is used in this example was "default".

To apply the changes reload the config by restarting the postfix service:

postfix stop
postfix start

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