SMTP server address in General settings is not it?

No, it isn't. The "SMTP server address" in "General settings" is the address of the SMTP server while the issue is related to the client (during smtp connection the client connects to the server, the server introduces itself and waits for the client to send its hostname, this kind of handshake is called HELO / EHLO).

You can get many details about the smtp connection steps and commands on http://www.samlogic.net/articles/smtp-commands-reference.htm

@netdesign problem not in the core Zend_Mail_Transport_Smtp. I see that the Mail->initSmtpTransport() do not use host value at all.
Piwik config.ini file contain host for mail transport but this is not a client hostname.
Maybe I can do PR for this.

Dear @Globulopolis, add the "client hostname" support in the Piwik config.ini would be an option, but I'm sure that setting "localhost" as default value in "$this->_name" is a fault because "localhost" is meaningless in the SMTP protocol (every host is localhost).

Even if you add the discussed variable in the Piwik config.ini, what would be the default value? What would happen if the user doesn't set the variable and leaves the software to choose it for him? It most likely will be "localhost" and the probem is here again (except that Piwik forces the user to set the value during the installation).

What I'd suggest is to report the issue to the upstream Zend team and adding, as just you said, the variable to the Piwik config.ini.

This will give the freedom to advanced users to set the "client hostname" to a custom value but will set automatically the variable with a meaningful value (the real hostname as known by the OS).

I hope you share my personal opinion.
Have a nice day ;)

Fabio (team Netdesign)

Dear @Globulopolis, I dont want to change Zend files so I have changed /piwik/core/Mail.php, function initSmtpTransport

if (!empty($mailConfig['heloname'])) { $smtpConfig['name'] = $mailConfig['heloname']; }

and added "heloname = example.org" in my config.ini.php. Now it works correctly.

Greetings from Cologne - Bernd

Dear @bglxx would you be so kind and post your /piwik/core/Mail.php and config.ini.php.
I am trying to setup ma configs according to your advices but without success. Many thanks in advance. Josef

Hello @bglxx I'm very unhappy but I don't have success for the mail sending feature even following both actions suggested by you (on the latest Matomo version 3.13.3).

I fixed again the ISSUE this time chaning Zend library on:

/libs/Zend/Mail/Transport/Smtp.php

changing in the contructor:

    public function __construct($host = '127.0.0.1', Array $config = array())
    {
        if (isset($config['name'])) {
            $this->_name = $config['name'];
        } else {
            $this->_name = gethostname();
        }

Dear @Globulopolis, I dont want to change Zend files so I have changed /piwik/core/Mail.php, function initSmtpTransport

if (!empty($mailConfig['heloname'])) { $smtpConfig['name'] = $mailConfig['heloname']; }

and added "heloname = example.org" in my config.ini.php. Now it works correctly.

Greetings from Cologne - Bernd

May I make pull request related to 90d65ae ?

@netdesign feel free to create one. However, it may not be needed because as part of Matomo 4 we're replacing the Mailer library see #14841 and the change would likely be undone again. We're hoping the new mailer library will fix things like these right away.

@tsteur it seems that #14841 is into discussion yet. And target milestone is 4.0.0. Isn't it?

Yes, we already started working on Matomo 4 and I reckon we will be working on that issue soon.

For 3.X we're only fixing mostly regressions and security issues now while we focus on Matomo 4.

Yes, we already started working on Matomo 4 and I reckon we will be working on that issue soon.

For 3.X we're only fixing mostly regressions and security issues now while we focus on Matomo 4.

Ok @tsteur thank you for your updates!

Still affected by this, for some reason my matomo instance identifies with the server's IPv6 address, even though the host name is configured correctly.

Actually it's not possible that you are affected by the exact same error. The problem was how Zend Mail was working. But we meanwhile replace Zend Mail with PHPMailer.

PHPMailer actually allows to set the Hostname, but we currently don't do that. So PHPMailer might try to identify the hostname itself by checking $_SERVER['SERVER_NAME'], gethostname(), php_uname('n'), or the value 'localhost.localdomain'.

We could add an additional configuration option though to allow overwriting the hostname...

I see there's a defaultHostnameIfEmpty config under global.ini.php, I'll try to set that up and see if it helps...

Edit: This resolved my issue.