Nodemailer connect to local docker-mailserver

Question

I need to set up a local mail server and send emails from it. I use docker-mailserver and try to connect to it from simple NodeJS script that uses Nodemailer. For docker-mailserver setup I followed the guide from its docs and changed only the DOMAINNAME env var to domain name of my server. The resulting docker port for container is:

993/tcp -> 0.0.0.0:993
143/tcp -> 0.0.0.0:143
25/tcp -> 0.0.0.0:25
587/tcp -> 0.0.0.0:587

From the same machine that runs mailserver docker container I tried to run the mail-sending script, here is it's code:

const nodemailer = require('nodemailer');

let transporter = nodemailer.createTransport({
    host: '0.0.0.0',
    port: 587,
    secure: false, // true for 465, false for other ports
    auth: {
        user: 'user@domain.com',
        pass: 'password'
    },
    tls: { rejectUnauthorized: false },
    debug: true,
});

let mailOptions = {
    from: '"👻" <user@domain.com>',
    to: 'some_account@gmail.com',
    subject: 'Hello ✔',
    text: 'Hello world?',
    html: '<b>Hello world?</b>'
};

transporter.verify((error) => {
    if (error) {
        return console.error(error);
    }

    transporter.sendMail(mailOptions, (error, info) => {
        if (error) {
            return console.error(error);
        }
        console.log('Message sent: %s', info.messageId);
    });
});

But I get only Error: Connection closed error.

What is the thing I'm missing here to setup correct connection between script and container?

Answer 1

By default container are isolated in docker. You can allow connection between containers in docker by adding link argument when creating your Container USAGE :

Docker run -d --name node_mailer --link EMAIL_SERVER_CONTAINER_NAME nodemailer_image