Mox Email Server

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

Quick Reference

Task Command/Location

Start/stop service systemctl start/stop/restart mox

View logs journalctl -u mox -f

Test config sudo -u mox /home/mox/mox config test

List accounts sudo -u mox /home/mox/mox config account list

Add account sudo -u mox /home/mox/mox config account add user@domain.com

Set password sudo -u mox /home/mox/mox setaccountpassword user@domain.com

Admin UI https://mail.domain.com/admin/

Webmail https://mail.domain.com/webmail/

Installation Workflow

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

• See dns-records.md

Install Mox - Download binary, run quickstart

• See administration.md

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

• See mox-config.md

Caddy Integration - Reverse proxy, certificate sync

• See caddy-integration.md

Create Accounts - Admin UI or CLI

• See administration.md

Architecture: Caddy + Mox

Internet → 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:

internal: 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:

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

UFW Firewall Rule

Allow Docker-to-host communication:

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

Reference Files

File When to Read

dns-records.md Setting up DNS for new domain

mox-config.md Editing mox.conf, understanding sconf format

caddy-integration.md Setting up reverse proxy, certificate sync

administration.md Managing accounts, domains, backups

troubleshooting.md Diagnosing issues with connectivity, TLS, delivery

Health Check

Run the included health check script:

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

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