Route Android Traffic Through a Secure Tunnel - A How-To Guide

Securing Your Android Data Connection with SSH Tunnels

A proactive approach to security, combining awareness and technical skill, can address many vulnerabilities. This article details how to protect your Android phone’s mobile data connection from unauthorized access using freely available software and a straightforward SSH tunnel.

We received a request from HTG Reader Michael, seeking guidance on extending the security benefits of an SSH server – previously set up on his home router – to his Android phone.

Dear HTG, I followed your instructions for establishing an SSH server on my router and configuring my laptop for secure connection. However, adapting this knowledge to my Android phone feels complex. Is there a simplified method to achieve the same level of home-link encryption on my phone as I have on my laptop? I have already successfully completed the original tutorial, establishing an SSH server on my router. Could you assist me? Sincerely, Michael

Michael, your self-assessment is modest. Your prior accomplishments – flashing your router, configuring the SSH server, and setting up your laptop client – demonstrate considerable technical proficiency.

Prerequisites and Understanding SSH

You’ll find this process quite manageable given your existing experience. If you are unfamiliar with SSH or its benefits for mobile device security, we recommend reviewing the "What Is and Why Setup a Secure Tunnel" section within our SSH router setup guide before proceeding.

Understanding the fundamentals of SSH is crucial for appreciating the security enhancements this method provides. It establishes an encrypted connection, safeguarding your data as it travels between your phone and your home network.

This method is particularly useful when connecting to public Wi-Fi networks, where the risk of interception is significantly higher. An SSH tunnel effectively creates a secure pathway for your data.

The following steps will guide you through the process of configuring your Android phone to utilize this secure connection. We will focus on practical implementation, building upon your existing SSH server setup.

Essential Requirements

This guide requires several components to function correctly. These include:

• An Android phone with root access, running Android OS 1.6 or a later version.
• A complimentary application of SSH Tunnel for Android.
• Access to a functioning SSH Server for connection purposes.

Let's clarify these prerequisites. Firstly, full configuration and deployment of SSH Tunnel for Android necessitate root privileges on your Android device. If your phone hasn't been rooted yet, we advise consulting our comprehensive guide, How to Root Your Android Device & Why You Might Want To, which details the rooting process and its benefits.

Secondly, this tutorial expands upon the concepts presented in our previous article, Setup SSH on Your Router for Secure Web Access from Anywhere. While replicating our exact setup – utilizing the integrated SSH server on a router with custom Tomato firmware – isn't mandatory, possessing an accessible SSH server is crucial. This server can be located on a remote host or within your home network.

From this point onward, we'll presume you possess, at a minimum, an SSH account complete with a username, password, and, ideally, an authorized key pair for enhanced security. Should any of these terms be unclear, revisiting the Setup SSH on your Router guide is highly recommended.

Establishing an SSH Tunnel on Android Devices

While several SSH tools exist for the Android platform, SSH Tunnel for Android is favored due to its straightforward configuration and usability. Its primary design goal was to assist users in regions, such as China, where internet access is heavily restricted and censored by governmental policies.

Installation and Initial Setup

The application can be downloaded free of charge from the Google Play Store. Alternatively, an APK file is available for manual installation if access to the Play Store is unavailable. Upon first launch, the application will present a configuration screen.

Avoid activating the "Tunnel Switch" initially, as no login credentials have been entered yet. Instead, navigate to the SSH Tunnel Settings menu to begin the configuration process.

Configuring Server Details and Authentication

Input your server’s IP address and the port number the SSH server is utilizing. The standard port for SSH is 22; maintain this setting unless specifically instructed otherwise by your SSH host.

Within the Account Information section, enter your username and password for the SSH server. This establishes a basic connection using password authentication.

For enhanced security, utilizing a key-pair is strongly recommended. If you require assistance generating a key-pair, consult the key generation section of our SSH router guide.

Note that key-pair configuration is managed on the SSH server side, not within the SSH Tunnel application. Refer to your server’s documentation for guidance.

Once the private key file (with a .ppk extension) is obtained, copy it to the /sdcard/sshtunnel/key/ directory on your device.

To enable key-based authentication, access the menu within the application, which will display the following interface:

Select Key File Manager and navigate to the /sshtunnel/key/ directory. Choose the appropriate key file for your server; consider naming keys descriptively (e.g., HomeRouter.ppk, SomeSSHService.ppk) if using the Profiles function for multiple servers.

Finalizing Configuration and Proxy Settings

With either password or key-based authentication configured, proceed to the final configuration steps.

Under the Port Forwarding section, enabling the built-in SOCKS proxy server is recommended to maximize application compatibility with SSH Tunnel. Simply check the "Use socks proxy" option.

Routing Options: Global vs. Individual Proxy

Determine whether to route all Android data traffic through the SSH server or selectively redirect specific applications.

Check "Global Proxy" to route the entire connection. For selective routing, choose "Individual Proxy" and select the desired applications, such as your web browser or social media apps.

Before activating the tunnel, review the remaining configuration options within the Feature Settings sub-section:

• Auto Connect: Automatically attempts to connect to the SSH server when available.
• Auto Reconnect: Automatically re-establishes the connection if it is unexpectedly lost.
• Enable GFW List: Specifically designed for users in China, this feature proxies only websites blocked by the Great Firewall.
• Enable DNS Proxy: This is enabled by default and is recommended. It routes all DNS requests through the SSH server, enhancing privacy. Disabling it sends DNS requests directly through your data connection.

Adjust these settings to your preferences. You are now prepared to test the connection.

Verifying Your SSH Tunnel Connection

To confirm that our SSH connection is functioning correctly, the initial step involves identifying the IP address of your mobile device. Launch the web browser on your phone and conduct a search on Google for "what is my ip". The search results will display your mobile data connection's IP address.