SSH IPv4 to IPv6 and vice-versa

What is SSH

Secure Shell (SSH) is a network protocol used to securely connect to a computer. It is often used to remotely access a command-line interface on a computer, such as a server. With SSH, you can remotely log in to a computer and run commands, transfer files, and manage networks. SSH is typically used to access servers, but it can also be used to access desktop computers, routers, and other devices. SSH is a secure way to access a remote computer because it encrypts the data being transmitted over the network. So on a Terminal or Command prompt of an operating system you would be using below command to connect to a remote host.

ssh username@ipv6 address

Why do we want to SSH to IPv6

The short answer is, because your server or remote computer uses an IPv6 protocol.
The long answer is: IPv6 addresses are larger than IPv4 addresses and can support more devices on the Internet. This is important because the number of devices connected to the Internet is growing rapidly, and we are running out of IPv4 addresses.

IPv6 address: 2001:db8:3333:4444:5555:6666:7777:8888
IPv4 address: or

IPv6 can support new Internet of Things (IoT) applications and technologies that require unique, globally-reachable addresses.

So for example, let's talk about Jio Fiber ISP (Internet Service Provider). Jio uses both IPv4 and IPv6 protocol, and with the help of its IPv6 protocol (with globally unique address) you can connect to a specific device in your home or office.

Why do we want to SSH to IPv6 from IPv4

Taking the above example of Jio Fiber, technically you can connect to your unique device from anywhere in the world. And it is easy to do so if you are no a same network, the server or PC or IoT device you want to connect to is in the same premises (office or home) and connected by same ISP (Internet Service provider), in our case Jio Fiber.
But what if you want to do it from any part of the world. (the cool thing)
Here comes the issue of connecting (SSH) from one ISP (lets say BSNL at a cybercafé) to another ISP (our Jio Fiber at home)

What's the issue - well, IPv4 and IPv6 are not directly compatible with each other and cannot communicate directly without some form of translation. This means that an IPv4 network cannot connect to an IPv6 network directly. Without going into much technicality, ISP like ACT, BSNL do not provide IPv6 out of the box. This means you cannot SSH into your IPv6 device.

I have been searching for a solution for some time, and here is what I learned.

How to SSH into IPv6 from an IPv4 network

Option 1: The TOR way
Option 2: Tunnel (sound like robbing a bank) 

The TOR way

The Tor network is a free, open-source network of servers that can be used to anonymize Internet traffic. It is not specifically designed to connect IPv4 to IPv6, but rather to provide anonymity and privacy for Internet users.

That being said, the Tor network does support both IPv4 and IPv6, and it is possible to use the Tor network to connect an IPv4 device to an IPv6 resource, or vice versa. This can be done by using a Tor relay that supports both IPv4 and IPv6.

For example, an IPv4 device can connect to the Tor network using an IPv4-only connection, and then exit the network through an IPv6-enabled relay to access an IPv6 resource. Alternatively, an IPv6 device can connect to the Tor network using an IPv6-only connection and exit the network through an IPv4-enabled relay to access an IPv4 resource.


An IPv6 tunnel is a type of network tunnel that allows IPv6 packets to be transmitted over an IPv4 network or vice versa. Tunnels are often used when a device or network needs to communicate with another device or network using a different protocol, but the underlying network does not support that protocol.

One of the way of using Tunnel is by using a Tunnel Broker Service. IPv6 tunnel broker is a server that provides tunneling services to clients, allowing them to connect IPv6 networks or devices to IPv4 networks or devices. Tunnel brokers work by creating a tunnel between the client and the broker, and then routing traffic between the client's IPv6 network and the IPv4 network.

Popular Tunnel Broker are Hurricane Electric & Route48

Check this post to know How to use TOR for SSH connection from IPv4 to IPv6

Till then Keep Safe, Wear Mask and Save Soil.

Prashant Verma

15 years of experience in Technical Textiles, Smart Textiles, and IoT, having worked with top multinational companies. I specialize in developing innovative products and solutions in these fields. With nine domestic and international patents, I’m passionate about pushing the boundaries of technology and sharing insights on the latest trends and innovations in the textile and IoT sectors. linkedin github external-link

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