Roundcube

Access Roundcube

• Open the following URL in your browser: https://<SERVER_IP>
• The installation uses a self-signed TLS certificate, so your browser will display a security warning. Accept the certificate to continue.
• HTTP requests on port 80 are automatically redirected to HTTPS.

Login

• Roundcube does not create or store mailbox accounts.
• Log in using the username and password of an existing mailbox on your configured IMAP server.

Configure Your Mail Server

The mail server connection settings are stored in: /root/roundcube/.env

Important settings:

• IMAP Host: IMAP_HOST
• IMAP Port: IMAP_PORT
• SMTP Host: SMTP_HOST
• SMTP Port: SMTP_PORT
• Username Domain: USERNAME_DOMAIN

The default configuration uses placeholder values:

IMAP_HOST=ssl://mail.example.org
IMAP_PORT=993

SMTP_HOST=tls://mail.example.org
SMTP_PORT=587

Update them with your actual mail server hostname.

After changing the settings, apply them with:

cd /root/roundcube && docker compose up -d

TLS Connection Types

Use the appropriate prefix for your mail server:

• ssl://: Implicit TLS, typically used with IMAP port 993 or SMTP port 465.
• tls://: STARTTLS, typically used with IMAP port 143 or SMTP port 587.

Self-Signed Mail Server Certificates

If your IMAP or SMTP server uses a self-signed certificate, Roundcube may reject the connection.

The optional TLS verification settings are located in: /root/roundcube/config/custom.inc.php

Uncomment and configure the relevant IMAP or SMTP connection options only when you trust the mail server and network.

Apply the configuration:

cd /root/roundcube && docker compose restart roundcube

Plugins & Skin

The default installation enables:

• archive
• zipdownload

Plugins are configured through the PLUGINS variable in: /root/roundcube/.env

For example:

PLUGINS=archive,zipdownload,managesieve

Apply the changes:

cd /root/roundcube && docker compose up -d

Bundled plugins such as managesieve, markasjunk, and enigma can be enabled by adding them to PLUGINS, when supported by the image.

For third-party plugins, add them to ROUNDCUBEMAIL_COMPOSER_PLUGINS in the Compose file and include their names in PLUGINS.

Manage Roundcube

View container status:

cd /root/roundcube && docker compose ps

View logs:

cd /root/roundcube && docker compose logs -f

Restart Roundcube:

cd /root/roundcube && docker compose restart roundcube

Stop the stack:

cd /root/roundcube && docker compose down

Start the stack:

cd /root/roundcube && docker compose up -d

Important Files & Directories

• Install Path: /root/roundcube
• Compose File: /root/roundcube/docker-compose.yml
• Environment File: /root/roundcube/.env
• Extra Configuration: /root/roundcube/config/custom.inc.php
• Database Volume: /var/lib/docker/volumes/roundcube_db_data
• Nginx Configuration: /etc/nginx/sites-available/roundcube
• TLS Certificate: /etc/nginx/ssl/roundcube.crt
• TLS Private Key: /etc/nginx/ssl/roundcube.key

Domain & HTTPS

1. Point your domain to the server's IP address (e.g., yourdomain.com;).

2. Install Certbot:

apt update
apt install -y certbot python3-certbot-nginx

3. Edit NGINX config and replace both server_name _; entries with your domain (e.g., server_name yourdomain.com;):

vim /etc/nginx/sites-available/roundcube

4. Issue a TLS certificate:

certbot certonly --nginx --non-interactive --agree-tos --email [email protected] -d yourdomain.com

5. Edit /etc/nginx/sites-available/roundcube and update the ssl_certificate and ssl_certificate_key directives to use your Let's Encrypt certificate.

Before:
    ssl_certificate     /etc/nginx/ssl/roundcube.crt;
    ssl_certificate_key /etc/nginx/ssl/roundcube.key;
After:
    ssl_certificate  /etc/letsencrypt/live/yourdomain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/yourdomain.com/privkey.pem;

6. Test the config:

nginx -t

7. Reload NGINX:

systemctl reload nginx

8. Open your browser and visit: https://yourdomain.com

Notes

• Roundcube is publicly accessible through Nginx on ports 80 and 443.
• The Roundcube container itself listens only on 127.0.0.1:8000.
• MariaDB is an internal Docker service and is not directly exposed to the host.
• The default web interface uses a self-signed TLS certificate.
• The upload limit is set to 25 MB; increase both UPLOAD_MAX_FILESIZE and Nginx's client_max_body_size for larger uploads.
• Change the Roundcube configuration based on your preferences.