Sshuttle over SSH

How to Set Up SSHuttle: A Transparent VPN Tunnel Over SSH

SSHuttle is a Python-based tool that allows you to create a VPN-like tunnel over an existing SSH connection. Unlike traditional SSH tunneling, SSHuttle works at a network layer level, forwarding all traffic through an SSH server as if you were physically located in the remote network. This is especially useful when you don’t want to manually configure specific ports for forwarding.

In this guide, we’ll walk through how to set up SSHuttle for transparent, on-the-fly tunneling.

Why Use SSHuttle?

• Transparent tunneling: It works on a network level and doesn't require configuring individual ports or services.

• No need to install extra software: It uses SSH, which is likely already set up on the remote machine.

• Simplicity: SSHuttle is simple to set up and requires no additional configuration on the remote server.

• Cross-platform: It works on Linux, macOS, and other Unix-like systems.

Installing SSHuttle

SSHuttle can be easily installed on most Linux distributions via the package manager:

sudo apt install sshuttle

Basic SSHuttle Command

Once SSHuttle is installed, you can start tunneling traffic with a simple command:

sshuttle -r [username]@[remote_host] [subnet]

• -r [username]@[remote_host]: Specifies the remote SSH server to connect to.

• [subnet]: The subnet you want to route traffic to. You can use 0/0 to route all traffic (which is commonly used for a full VPN tunnel).

Example:

sshuttle -r [e-mail] 0/0

This will route all traffic from your local machine through the SSH connection to remote-server.com, effectively creating a VPN-like tunnel.

Advanced SSHuttle Usage

1. Specifying Local Ports

If you only want to route specific IP addresses or networks through the SSH tunnel, you can specify a particular subnet.

sshuttle -r [e-mail] 192.168.1.0/24

This will only route traffic destined for 192.168.1.0/24 through the SSH server.

2. Setting Up DNS Forwarding

By default, SSHuttle doesn’t forward DNS queries, which means DNS requests might not resolve correctly when using the tunnel. To ensure DNS queries are forwarded through the tunnel, use the -D option:

sshuttle -r [e-mail] -D 0/0

This will ensure that DNS queries, along with other traffic, are routed through the tunnel.

3. Specifying a Local Gateway

In some cases, you may want to specify which local network interface SSHuttle uses. To do this, you can use the -g flag:

sshuttle -r [e-mail] -g eth0 0/0

This will force SSHuttle to use the eth0 interface for routing traffic.

4. Running SSHuttle in the Background

If you don’t want to keep the terminal session open, you can run SSHuttle in the background using the -d flag:

sshuttle -r [e-mail] -d 0/0 &

This will start the SSHuttle process in the background.

Checking the Tunnel

To verify that SSHuttle is running and that your traffic is routing through the remote server, you can check your IP address using an online service like WhatIsMyIP.com. If the SSH tunnel is working, your IP address should appear as that of the remote server.

You can also use network diagnostic tools like traceroute or ping to confirm that your traffic is being routed correctly.

Stopping the SSHuttle Tunnel

To stop SSHuttle, simply press Ctrl+C in the terminal where it’s running, or find and kill the process manually:

1. Find the process ID (PID) of SSHuttle:

   ps aux | grep sshuttle

2. Kill the process:

   kill [PID]

Troubleshooting

• Permission Denied: If you encounter a "Permission Denied" error, make sure that your SSH key is correctly configured and that you have the appropriate permissions on the remote server.

• DNS Issues: If you’re having DNS issues, try using the -D flag to forward DNS queries.

• No Route to Host: If you receive a "No route to host" error, make sure the remote server is accessible and that you’re specifying the correct subnet.