Deploy On A Subdomain

Use one subdomain for the admin dashboard and one for the SMTP service. Keep the dashboard behind HTTPS and keep real sending disabled until DNS and reputation checks are ready.

Web Panel panel.yourdomain.com HTTPS dashboard

SMTP Host smtp.yourdomain.com Customer SMTP hostname

API Port 8080 Private behind Nginx

SMTP Port 2525/587 Submission port

Create DNS Records

Add these at your domain registrar or DNS provider.

panel.yourdomain.com  A  YOUR_SERVER_IP
smtp.yourdomain.com   A  YOUR_SERVER_IP

# Reverse DNS/PTR is set at your VPS/server provider:
YOUR_SERVER_IP -> smtp.yourdomain.com

Upload The App

From your local project folder, copy the app to the server.

scp -r . root@YOUR_SERVER_IP:/opt/independent-smtp-provider

Configure Environment

On the server, set production values. Start in file mode first.

cd /opt/independent-smtp-provider
cp .env.example .env
nano .env

PUBLIC_HOSTNAME=smtp.yourdomain.com
API_HOST=127.0.0.1
API_PORT=8080
SMTP_HOST=0.0.0.0
SMTP_PORT=2525
SMTP_TRANSPORT=file
ADMIN_TOKEN=use-a-long-random-secret

Run With PM2

PM2 keeps the Node app alive after you close SSH.

npm install -g pm2
npm install
node cli.js init
pm2 start src/index.js --name smtp-provider
pm2 save
pm2 startup

Nginx Reverse Proxy

Expose the dashboard on HTTPS without exposing port 8080 directly.

server {
  server_name panel.yourdomain.com;

  location / {
    proxy_pass http://127.0.0.1:8080;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
  }
}

Add HTTPS

After Nginx is configured and DNS points to the server, issue TLS.

sudo nginx -t
sudo systemctl reload nginx
sudo certbot --nginx -d panel.yourdomain.com

Open Firewall Ports

Use 80/443 for the panel and 2525 or 587 for SMTP submission.

sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw allow 2525/tcp
# Later, if using standard submission:
sudo ufw allow 587/tcp

Turn On Real Sending Later

Only switch to direct mode after SPF, DKIM, DMARC, PTR/rDNS, TLS, abuse mailbox, and warmup are ready.

SMTP_TRANSPORT=direct
pm2 restart smtp-provider --update-env

Customer DNS

Generated per customer domain

When you run node cli.js create-domain <accountId> customer.com, the app prints the TXT records the customer must publish for ownership and DKIM. Do not allow sending from a customer domain until those records verify.