Investigate MailPoet

[nate-allen]

It looks like MailPoet can be setup to send emails without using wp_mail. Look into how it does send email, and if we can disable that feature. If not, we may need to add the plugin to the deny list.

[NickGreen]

Adding plugin to the denylist in the short term. If this issue turns up a better solution, feel free to remove it as needed.

[gin0115]

The mailer options are saved in the {prefix_}mailpoet_settings table.

---

You can force the mailer to use PHP by setting

• smtp_provider = server.
• mta you need to set the method value as PHPMail

a:14:{s:22:"mailpoet_api_key_state";a:3:{s:18:"access_restriction";s:0:"";s:4:"data";a:1:{s:11:"is_approved";s:5:"false";}s:5:"state";s:11:"check_error";}s:14:"authentication";s:1:"1";s:10:"encryption";s:0:"";s:8:"password";s:3:"pgq";s:5:"login";s:2:"gq";s:7:"api_key";s:0:"";s:10:"secret_key";s:0:"";s:10:"access_key";s:0:"";s:6:"region";s:9:"us-east-1";s:4:"port";s:4:"2424";s:4:"host";s:14:"smtp.null.void";s:16:"mailpoet_api_key";s:0:"";s:9:"frequency";a:2:{s:8:"interval";s:1:"5";s:6:"emails";s:2:"25";}s:6:"method";s:7:"PHPMail";}

...

Array
(
    [mailpoet_api_key_state] => Array
        (
            [access_restriction] => 
            [data] => Array
                (
                    [is_approved] => false
                )

            [state] => check_error
        )

    [authentication] => 1
    [encryption] => 
    [password] => pgq
    [login] => gq
    [api_key] => 
    [secret_key] => 
    [access_key] => 
    [region] => us-east-1
    [port] => 2424
    [host] => smtp.null.void
    [mailpoet_api_key] => 
    [frequency] => Array
        (
            [interval] => 5
            [emails] => 25
        )

    [method] => PHPMail
)

• Setting the method as PHPMail is the only change needed.

There is another DB key called web_host, this can be set to manual (probably no needed)

---

Or you can set fake SMTP using

• smtp_provider = manual
• mta you will need to update
  • host as some fake host
  • port as some fake port
  • login as some fake username
  • password as some fake password
  • method as SMTP

a:14:{s:22:"mailpoet_api_key_state";a:3:{s:18:"access_restriction";s:0:"";s:4:"data";a:1:{s:11:"is_approved";s:5:"false";}s:5:"state";s:11:"check_error";}s:14:"authentication";s:1:"1";s:10:"encryption";s:0:"";s:8:"password";s:3:"pgq";s:5:"login";s:2:"gq";s:7:"api_key";s:0:"";s:10:"secret_key";s:0:"";s:10:"access_key";s:0:"";s:6:"region";s:9:"us-east-1";s:4:"port";s:4:"2424";s:4:"host";s:14:"smtp.null.void";s:16:"mailpoet_api_key";s:0:"";s:9:"frequency";a:2:{s:8:"interval";s:1:"5";s:6:"emails";s:2:"25";}s:6:"method";s:4:"SMTP";}

...

Array
(
    [mailpoet_api_key_state] => Array
        (
            [access_restriction] => 
            [data] => Array
                (
                    [is_approved] => false
                )

            [state] => check_error
        )

    [authentication] => 1
    [encryption] => 
    [password] => pgq        <<==
    [login] => gq            <<==
    [api_key] => 
    [secret_key] => 
    [access_key] => 
    [region] => us-east-1
    [port] => 2424           <<==
    [host] => smtp.null.void <<==
    [mailpoet_api_key] => 
    [frequency] => Array
        (
            [interval] => 5
            [emails] => 25
        )

    [method] => SMTP <<==
)

[BrianHenryIE]

I wasn't aware of that hook solution.

I approached a similar problem by loading the PHPMailer class early and replacing it with a subclass of my own where I overrode the send method.

https://github.com/BrianHenryIE/bh-wp-one-click-list-unsubscribe-mailto-header/blob/50fbdf36ae028d0d09e8849ef9ffd0da170980bf/src/Integrations/class-mailpoet.php#L50

https://github.com/BrianHenryIE/bh-wp-one-click-list-unsubscribe-mailto-header/blob/50fbdf36ae028d0d09e8849ef9ffd0da170980bf/src/API/class-phpmailer-intercept.php#L7

Didn't really test it much.