The docker image has not any SMTP server

[vampolo]

when wordpress tries to use the php mail function the mail is not sent because there is not any SMTP server on the container.

How would you suggest to handle this functionality?

[eugeneware]

I would point the SMTP server to your actual SMTP server, or use something like SendGrid (which is how Heroku does this).

And use a plugin like this: http://serversmtp.com/en/smtp-wordpress-configure

To change the SMTP settings.

[jrthib]

What about installing postfix which would give this the option to work out of the box? Additionally the user could opt to send their SMTP elsewhere.

[lvnilesh]

or use mandrill SMTP if you prefer https://wordpress.org/plugins/wpmandrill/

[denzuko]

Or use google smtp. The point being a smtp server does not need to be local to the web application server. Especially within a containerized environment where its easier to just do docker run catatnight/postfix to have a full email server up and running without having your web server open to hacks.