Mailserver Ansible

Ansible playbook that deploys and hardens a Stalwart all-in-one mail server on Ubuntu.

What it does

Role	Purpose
`base`	apt upgrades, unattended-upgrades, timezone, swap, sysctl hardening
`ssh`	Key-only root login, disable password auth, rate limiting
`ufw`	Firewall — deny all incoming except SSH, SMTP, IMAP, HTTPS
`fail2ban`	Brute force protection for SSH + Stalwart auth
`stalwart`	Stalwart mail server with built-in ACME (Let's Encrypt)

Prerequisites

Ubuntu server with root SSH key access
DNS: mail.rubenhensen.nl → server IP (A record)
DNS: MX record for your domain pointing to mail.rubenhensen.nl
Ansible installed locally (brew install ansible)

Setup

cd ~/Repos/k8scd/ansible/mailserver

# 1. Create vault password file (gitignored)
echo 'your-vault-password' > .vault_pass
chmod 600 .vault_pass

# 2. Create encrypted secrets
ansible-vault create host_vars/mailserver/vault.yml
# Add:
#   ---
#   vault_stalwart_fallback_admin_password: "your-admin-password"

# 3. Edit inventory if server IP changed
#    inventory.yml → ansible_host

# 4. Run
ansible-playbook playbook.yml

Day-to-day operations

Re-run after config changes:

ansible-playbook playbook.yml

Edit encrypted secrets:

ansible-vault edit host_vars/mailserver/vault.yml

Run only a specific role:

ansible-playbook playbook.yml --tags stalwart

(Note: tags aren't configured yet — use --start-at-task "task name" or add tags if needed)

Upgrade Stalwart: Bump stalwart_version in roles/stalwart/defaults/main.yml and re-run. It only re-downloads when the version changes.

File structure

├── ansible.cfg              # Ansible settings + vault password file path
├── inventory.yml            # Server IP, SSH user, python interpreter
├── .vault_pass              # Vault password (gitignored)
├── .gitignore
├── host_vars/mailserver/
│   ├── vars.yml             # Maps variables to vault references
│   └── vault.yml            # Encrypted secrets (committed as ciphertext)
└── roles/
    ├── base/                # OS hardening + swap
    ├── ssh/                 # sshd_config template
    ├── ufw/                 # Firewall rules
    ├── fail2ban/            # Jails for SSH + Stalwart
    └── stalwart/            # Mail server install + config.toml template

Stalwart admin

Web admin: https://mail.rubenhensen.nl Login: admin / (password from vault)

From the web UI you can manage domains, accounts, DKIM keys, and other mail settings.

TLS certificates

Handled automatically by Stalwart's built-in ACME support (Let's Encrypt, tls-alpn-01 challenge on port 443). No certbot needed. Certificates auto-renew.

Ports

Port	Service
22	SSH
25	SMTP
465	SMTP submission (implicit TLS)
587	SMTP submission (STARTTLS)
993	IMAP (implicit TLS)
443	HTTPS (web admin + JMAP + ACME)
8080	HTTP

If something breaks

Stalwart logs: /opt/stalwart/logs/
Stalwart config: /opt/stalwart/etc/config.toml
Service status: systemctl status stalwart
fail2ban status: fail2ban-client status / fail2ban-client status sshd
Firewall: ufw status
Check banned IPs: fail2ban-client status stalwart-auth
Unban an IP: fail2ban-client set <jail> unbanip <ip>

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