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name: mox-email-server description: | Mox email server installation, configuration, and administration. Use when: (1) Setting up Mox mail server on a VPS (2) Configuring DNS records for email (MX, SPF, DKIM, DMARC, MTA-STS) (3) Integrating Mox with Caddy reverse proxy and Docker (4) Managing email accounts, domains, and aliases (5) Troubleshooting email delivery, TLS, or connectivity issues (6) Syncing TLS certificates from Caddy to Mox

Mox Email Server

Mox is a modern, self-hosted email server written in Go. This skill covers installation, Caddy integration, and administration.

Quick Reference

Installation Workflow

1. DNS Setup - Configure A, MX, SPF, DMARC records

   • See dns-records.md

2. Install Mox - Download binary, run quickstart

   • See administration.md

3. Configure for Docker - Add Docker bridge IPs, set up listeners

   • See mox-config.md

4. Caddy Integration - Reverse proxy, certificate sync

   • See caddy-integration.md

5. Create Accounts - Admin UI or CLI

   • See administration.md

Architecture: Caddy + Mox

CopyInternet → Caddy (Docker, ports 80/443) → Mox (Host, port 8080) [Web UI]
Internet → Mox (Host, ports 25/465/587/993) [SMTP/IMAP]

Caddy handles:

• TLS certificates via ACME
• Reverse proxy for web interfaces (admin, webmail, autoconfig, MTA-STS)

Mox handles:

• SMTP (25), SMTPS (465), Submission (587), IMAPS (993)
• Web interfaces on port 8080

Certificate sync: Caddy obtains certs → systemd timer copies to Mox → Mox uses for SMTP/IMAP TLS.

Critical Configuration Points

Docker Bridge IPs in mox.conf

Mox internal listener must include Docker bridge IPs for Caddy to reach it:

Copyinternal:
    IPs:
        - 127.0.0.1
        - ::1
        - 172.17.0.1
        - 172.18.0.1
        - 172.19.0.1
        - 172.20.0.1
        - 172.21.0.1
        - 172.22.0.1
    Hostname: localhost

Caddyfile Admin Path

Admin interface requires Host header rewrite:

Copyhandle /admin/* {
    reverse_proxy host.docker.internal:8080 {
        header_up Host localhost
    }
}

UFW Firewall Rule

Allow Docker-to-host communication:

Copysudo ufw allow from 172.16.0.0/12 to any port 8080 comment 'Docker to mox'

Reference Files

Health Check

Run the included health check script:

Copysudo scripts/mox-health-check.sh [PUBLIC_IP]

Checks: service status, port connectivity, certificate validity, configuration, recent errors.