🔌 vps_tunnel.sh

A Bash script that automatically discovers open TCP ports on your local machine and tunnels them securely to a VPS using autossh. Ideal for homelab setups with limited access due to CGNAT, where incoming connections from the VPS side are impossible.

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🚀 Features

• 🔍 Auto-discovers running local TCP services (via ss)
• 📤 Securely forwards all open ports to your VPS over SSH with autossh
• 🔁 Persistent tunnels using autossh (auto-reconnect)
• ⚙️ Exclusion config lets you skip noisy or sensitive ports
• 🧠 Interactive prompts for exclusion and saving config
• 💾 Writes a PID file to /tmp/ for easy tunnel tracking

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📦 Requirements

• bash
• autossh
• ss (usually part of iproute2)
• awk, sed, sort, uniq
• GatewayPorts clientspecified In /etc/ssh/sshd_config on the remote vps

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🧰 Installation

Clone the repo and make the script executable:

git clone https://github.com/yourusername/vps_tunnel.git
cd vps_tunnel
chmod +x vps_tunnel.sh

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⚙️ Usage

./vps_tunnel.sh [options]

Options:

Flag	Description	Default
-u USER	SSH username for VPS	root
-h HOST	VPS hostname or IP	gate.lab
-P PORT	SSH port on VPS	22
-d IP	Device IP suffix (127.0.0.X)	58
-c CONFIG	Path to excluded ports config	~/.config/vps_tunnel-xport.conf
-?	Show help	—

Example:

./vps_tunnel.sh -u root -h 146.234.156.34 -P 34898 -d 59 -c ~/.config/vps_exclude.conf

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🧠 How It Works

1. Scans for open TCP ports and the processes using them via ss.
2. Prompts you to exclude any of them.
3. Builds reverse SSH tunnels like:

   -R 127.0.0.59:80:127.0.0.1:80
   

4. Launches autossh to maintain the tunnel.
5. Writes a PID file to /tmp/vps_tunnel_59.pid.

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📂 Exclusion Config

If you run the script multiple times, it remembers which ports you excluded last time using a config file:

~/.config/vps_tunnel-xport.conf

You can edit this manually or via the script's interactive prompt.

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🧪 Monitoring

The actual SSH tunnel can be inspected via:

ps aux | grep autossh
cat /tmp/vps_tunnel_58.pid

Or test a forwarded port from the VPS side:

curl http://127.0.0.58:8080

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🔐 Security Considerations

• Ensure your VPS user is restricted (e.g., key-only login, limited shell if needed).
• Consider firewalling or service-authenticating your forwarded ports on the VPS.

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