137 lines
2.9 KiB
Markdown
137 lines
2.9 KiB
Markdown
# Mail Relay - SMTP de salida para stacks
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Stack de relay SMTP interno para centralizar el envio de correos de tus apps sin montar un servidor de correo completo.
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## 📋 Descripcion
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Este stack despliega un relay SMTP con Postfix usando `boky/postfix` para:
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- Recibir correo SMTP desde contenedores internos
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- Reenviar todo a un proveedor SMTP externo (smarthost)
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- Firmar con DKIM (autogenerado)
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- Unificar configuracion de correo para todos los stacks
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No incluye recepcion de correo (MX, IMAP, POP3, webmail).
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## 🚀 Despliegue
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### 1. Preparar rutas y secreto en el host
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```bash
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sudo mkdir -p /opt/mail-relay/{queue,opendkim,secrets}
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sudo chmod 700 /opt/mail-relay/secrets
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printf '%s' 'CAMBIA_ESTA_PASSWORD_SMTP' | sudo tee /opt/mail-relay/secrets/relayhost_password > /dev/null
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sudo chmod 600 /opt/mail-relay/secrets/relayhost_password
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```
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### 2. Desplegar desde Portainer
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1. Ve a **Stacks** -> **Add stack**
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2. Nombre: `mail-relay`
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3. Configura el repositorio Git
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4. Compose path: `mail-relay/docker-compose.yml`
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5. Carga variables desde `mail-relay/stack.env`
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6. Ajusta al menos:
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- `MAIL_RELAY_HOSTNAME`
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- `MAIL_RELAY_ALLOWED_SENDER_DOMAINS`
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- `MAIL_RELAY_MASQUERADED_DOMAINS`
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- `MAIL_RELAY_SMARTHOST`
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- `MAIL_RELAY_SMARTHOST_USERNAME`
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7. Deploy del stack
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## ⚙️ Variables importantes
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```env
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MAIL_RELAY_SMARTHOST=[smtp.proveedor.tld]:587
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MAIL_RELAY_SMARTHOST_USERNAME=usuario-smtp
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MAIL_RELAY_SMTP_TLS_SECURITY_LEVEL=encrypt
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MAIL_RELAY_ALLOWED_SENDER_DOMAINS=tudominio.com
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MAIL_RELAY_MASQUERADED_DOMAINS=tudominio.com
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```
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La password SMTP no se pone en `stack.env`; se lee desde el archivo host:
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```text
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/opt/mail-relay/secrets/relayhost_password
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```
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## 🔌 Conectar otras apps
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En cada stack que deba enviar correo, añade la red externa:
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```yaml
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networks:
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mail_internal:
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external: true
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```
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Y en el servicio de la app:
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```yaml
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services:
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tu-app:
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networks:
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- default
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- mail_internal
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```
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Config SMTP en la app:
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```env
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SMTP_HOST=mail-relay
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SMTP_PORT=587
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SMTP_FROM=noreply@tudominio.com
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```
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## ✅ DNS minimo recomendado
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Para buena entregabilidad en Gmail/Outlook:
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- SPF
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- DKIM
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- DMARC
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### SPF (ejemplo)
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```text
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v=spf1 include:spf.tu-proveedor.tld ~all
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```
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### DKIM
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Tras el primer arranque, extrae el TXT generado:
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```bash
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find /opt/mail-relay/opendkim -type f -name '*.txt' -exec echo '### {}' \; -exec cat {} \;
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```
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Copia esos valores a tu DNS.
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### DMARC (inicio en monitorizacion)
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```text
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v=DMARC1; p=none; adkim=s; aspf=s
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```
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## 🧪 Prueba rapida
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```bash
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docker exec -i mail-relay sendmail -t <<'EOF'
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From: noreply@tudominio.com
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To: destino@example.com
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Subject: prueba mail relay
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Correo de prueba del stack mail-relay.
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EOF
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```
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## 🛠️ Troubleshooting
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Ver logs:
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```bash
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docker logs -f mail-relay
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```
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Errores tipicos:
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- `Relay access denied`: revisa `MAIL_RELAY_ALLOWED_SENDER_DOMAINS`
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- Auth fallida con proveedor: revisa usuario/password SMTP
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- Rechazo por DNS: valida SPF/DKIM/DMARC |