Firewall and Port Blocking

Oct 13, 2025 by wbrum.org 49 views

Introduction

Deploying applications to a Raspberry Pi can be a straightforward process, but when the Pi is connected to a Virtual Private Network (VPN), things can get complicated. In this article, we will explore the challenges of auto-deploying to a Pi on a VPN and provide a solution to overcome these obstacles.

Understanding VPNs and Their Impact on Auto-Deploy

A VPN creates a secure and encrypted connection between your device and a VPN server. This connection masks your IP address, making it appear as though you are accessing the internet from a different location. While VPNs provide excellent security and anonymity, they can also interfere with auto-deployment processes.

When a Pi is connected to a VPN, it may not be able to access the internet or communicate with external services, making it difficult to deploy applications. This is because the VPN connection can block or redirect traffic, causing auto-deployment scripts to fail.

Challenges of Auto-Deploying to a Pi on a VPN

IP Address Changes

One of the main challenges of auto-deploying to a Pi on a VPN is the dynamic IP address. When a Pi is connected to a VPN, its IP address may change frequently, making it difficult to configure auto-deployment scripts to access the Pi.

Firewall and Port Blocking

VPNs often have strict firewall rules and port blocking policies, which can prevent auto-deployment scripts from accessing the Pi. This can cause scripts to fail or timeout, leading to deployment failures.

DNS Resolution Issues

VPNs can also cause DNS resolution issues, making it difficult for auto-deployment scripts to resolve the Pi's hostname or IP address.

Solution: Using SSH and Port Forwarding

To overcome the challenges of auto-deploying to a Pi on a VPN, we can use SSH and port forwarding. SSH (Secure Shell) is a secure protocol for remote access to a Pi, while port forwarding allows us to forward traffic from a local port to a remote port on the Pi.

Setting Up SSH

To set up SSH on your Pi, follow these steps:

Install the SSH server package on your Pi: sudo apt-get install openssh-server
Start the SSH server: sudo service ssh start
Configure the SSH server to allow remote access: sudo nano /etc/ssh/sshd_config (add PermitRootLogin yes and PasswordAuthentication yes)

Setting Up Port Forwarding

To set up port forwarding, follow these steps:

Install the sshuttle package on your Pi: sudo apt-get install sshuttle
Configure the sshuttle package to forward traffic from a local port to a remote port on the Pi: sudo nano /etc/sshuttle.conf (add forward 8080 8080)

Using SSH and Port Forwarding for Auto-Deploy

To use SSH and port forwarding for auto-deploy, follow these steps:

Set up a SSH connection to your Pi using a tool like sshuttle
Configure your auto-deployment script to use the SSH connection and port forwarding
Run the auto-deployment script to deploy your application to the Pi

Example Use Case: Auto-Deploying a Flask Application

Here's an example use case of auto-deploying a Flask application to a Pi on a VPN using SSH and port forwarding:

Flask Application Code

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello_world():
    return "Hello, World!"

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8080)

Auto-Deployment Script

#!/bin/bash

# Set up SSH connection
sshuttle -r user@pi_ip -p 8080

# Deploy Flask application
git clone https://github.com/user/flask_app.git
cd flask_app
pip install -r requirements.txt
python app.py

Running the Auto-Deployment Script

To run the auto-deployment script, save it to a file (e.g., deploy.sh) and make it executable: chmod +x deploy.sh. Then, run the script: ./deploy.sh.

Conclusion

Introduction

In our previous article, we explored the challenges of auto-deploying to a Raspberry Pi on a Virtual Private Network (VPN) and provided a solution using SSH and port forwarding. In this article, we will answer some frequently asked questions (FAQs) about auto-deploying to a Pi on a VPN.

Q: What is the difference between SSH and port forwarding?

A: SSH (Secure Shell) is a secure protocol for remote access to a Pi, while port forwarding is a technique that allows us to forward traffic from a local port to a remote port on the Pi. SSH is used to establish a secure connection to the Pi, while port forwarding is used to forward traffic to the Pi.

Q: Why do I need to use SSH and port forwarding to auto-deploy to a Pi on a VPN?

A: When a Pi is connected to a VPN, its IP address may change frequently, making it difficult to configure auto-deployment scripts to access the Pi. SSH and port forwarding allow us to establish a secure connection to the Pi and forward traffic to the Pi, even if its IP address changes.

Q: How do I set up SSH on my Pi?

A: To set up SSH on your Pi, follow these steps:

Install the SSH server package on your Pi: sudo apt-get install openssh-server
Start the SSH server: sudo service ssh start
Configure the SSH server to allow remote access: sudo nano /etc/ssh/sshd_config (add PermitRootLogin yes and PasswordAuthentication yes)

Q: How do I set up port forwarding on my Pi?

A: To set up port forwarding on your Pi, follow these steps:

Install the sshuttle package on your Pi: sudo apt-get install sshuttle
Configure the sshuttle package to forward traffic from a local port to a remote port on the Pi: sudo nano /etc/sshuttle.conf (add forward 8080 8080)

Q: What is the difference between `sshuttle` and `ssh`?

A: sshuttle is a tool that allows us to forward traffic from a local port to a remote port on the Pi, while ssh is a tool that allows us to establish a secure connection to the Pi. sshuttle is used for port forwarding, while ssh is used for remote access.

Q: How do I use SSH and port forwarding for auto-deploy?

A: To use SSH and port forwarding for auto-deploy, follow these steps:

Set up a SSH connection to your Pi using a tool like sshuttle
Configure your auto-deployment script to use the SSH connection and port forwarding
Run the auto-deployment script to deploy your application to the Pi

Q: What are some common issues that I may encounter when using SSH and port forwarding for auto-deploy?

A: Some common issues that you may encounter when using SSH and port forwarding for auto-deploy include:

IP address changes: If the Pi's IP address changes, you may need to update the SSH connection and port forwarding configuration.
Firewall and port blocking: If the VPN has strict firewall rules and port blocking policies, you may need to configure the SSH connection and port forwarding to work around these issues.
DNS resolution issues: If the Pi's hostname or IP address cannot be resolved, you may need to update the SSH connection and port forwarding configuration.

Q: How do I troubleshoot issues with SSH and port forwarding for auto-deploy?

A: To troubleshoot issues with SSH and port forwarding for auto-deploy, follow these steps:

Check the SSH connection and port forwarding configuration to ensure that it is correct.
Check the Pi's IP address and hostname to ensure that they are correct.
Check the VPN's firewall rules and port blocking policies to ensure that they are not interfering with the SSH connection and port forwarding.
Check the DNS resolution to ensure that it is working correctly.

Conclusion

In this article, we answered some frequently asked questions (FAQs) about auto-deploying to a Raspberry Pi on a Virtual Private Network (VPN) using SSH and port forwarding. We hope that this article has been helpful in answering your questions and providing you with a better understanding of how to use SSH and port forwarding for auto-deploy.