I want to create a tunnel between my custom domain (e.g., backend.dinhanhthi.com) and my locally hosted server (e.g., http://localhost:3000). For this, I'll use Cloudflare's Zero Trust, which is free.

You can access Zero Trust from the Cloudflare dashboard or via this link.

Follow these steps: Create a tunnel → Choose Cloudflared → Give it a name → Save tunnel → (install cloudflared following the docs) and then:

1. Either activate it once for the current session using cloudflared tunnel run...
2. Or install it permanently on your machine to run automatically at startup by using sudo cloudflared service install ...

Next, click "Next" and configure Public hostnames:

• Subdomain: backend
• Domain: dinhanhthi.com (select from the list)
• Path: leave empty
• Service: HTTP (Type) and localhost:3000 (URL)

Then click "Complete setup."

You can now check the result based on the option you chose earlier (cloudflared tunnel run or sudo cloudflared service install...).

Remarks:

• To add another subdomain and port, simply modify the existing tunnel and add more public hostnames. No need to create a new tunnel.
• This solution doesn't work when you have an active VPN on your computer!

If you don't have a custom domain and need a simpler solution, consider using ngrok instead.