Forem: Kevin Suchetan

How to SSH Into a VirtualBox Ubuntu VM From Windows - Password Authentication (Step-By-Step Guide)

Kevin Suchetan — Mon, 17 Nov 2025 19:00:37 +0000

If you're running Ubuntu in VirtualBox on Windows and want to SSH into it from your Windows terminal - this guide walks you through everything clearly.

This is perfect if you want to:

Practice Linux server administration
Access your VM like a remote machine
Simulate multiple user sessions
Run commands from Windows without using the VM window

Let’s get started.

Step-1. Install OpenSSH Server Inside the Ubuntu VM

Open your Ubuntu terminal and switch to root (optional but convenient):

sudo -i

Install the SSH server:

apt install openssh-server

Check whether SSH server is running:

systemctl status ssh

If you see "active (running)", you're good.

Step-2. Enable Password Authentication (Optional but Needed Here)

SSH sometimes disables password login by default.

Open the SSH server config:

nano /etc/ssh/sshd_config

Find this line:

#PasswordAuthentication no

Change it to:

PasswordAuthentication yes

Save and exit(Ctrl X and then 'y'), then restart SSH:

systemctl restart ssh

Step-3. Set Up VirtualBox Port Forwarding (The Key Step)

Your VM is behind VirtualBox's NAT network, which means:

It can access the internet
But outside machines (like Windows) cannot access the VM directly

To allow SSH traffic from Windows to Ubuntu VM, we create a forwarding rule.

In VirtualBox:

i. Select your Ubuntu VM

ii. Settings > Network > Adapter 1

iii. Attached to: NAT

iv. Click Advanced > Port Forwarding

Add rule:

Name	Protocol	Host IP	Host Port	Guest IP	Guest Port
SSH	TCP	127.0.0.1	2222		22

(Guest IP can be left blank - VirtualBox fills it automatically)

This tells VirtualBox: "When Windows sends traffic to 127.0.0.1:2222, forward it to the VM's port 22."

Step-4. Check if Windows Has the SSH Client

Windows 10 and 11 already ship with OpenSSH client.

Use Windows terminal to Verify:

ssh -V

If you get a version number, it's installed.

If not, enable it:
Settings > System > Optional features > Add a feature > "OpenSSH Client"
No firewall changes are usually needed since outbound connections are allowed.

Step-5. SSH From Windows Into the Ubuntu VM

Open Windows Terminal or CMD and run:

ssh -p 2222 <your-ubuntu-username>@127.0.0.1

Enter your Ubuntu user password - and you're inside the VM from Windows!

Wrap-Up

With just NAT port forwarding and a few configuration tweaks, your Windows machine can SSH into your Ubuntu VM exactly like a real remote server. Perfect for learning Linux, DevOps, or cloud workflows.

If you found this helpful, drop a comment - happy hacking!

Creating a Docker Image from a Running Container

Kevin Suchetan — Fri, 01 Aug 2025 03:34:22 +0000

If you've made changes inside a running Docker container and want to save those changes, you can commit the container as a new image. In this short guide, we'll walk through how to do that:

Let's create a simple Express app with just one file, index.js, and then build a Docker image from it. After that, we'll run a container using that image. Once the container is up and running, we'll make changes to the code inside the container and then commit those changes into a new Docker image.

index.js

const express = require('express');
const app = express();

app.get('/', (req, res) => {
    res.send("Welcome to Home Page");
});

app.listen(8080, () => console.log("Server Listening on 8080"));

Dockerfile

FROM node:14-alpine

WORKDIR '/usr/app/'

COPY './package.json' ./
RUN npm install
COPY ./ ./

CMD ["npm", "start"]

After creating the Dockerfile, run the build command:

docker build -t kevin3302/express-app .

Now, let's run the container:

docker run -p 5000:8080 kevin3302/express-app

We can access the website at http://localhost:5000.

Now that our container is running, the next step is to access it and make the necessary code changes. To do that, we first need to find the container ID.

Step-1: Check the container ID

To get the container ID of the running container, In a new terminal run:

docker ps

This will list all running containers with their IDs, names, and other details. We'll need the container ID to access the container and modify the code inside.

Now, we'll enter the shell of the running container to modify the code directly inside it.

Step 2: Enter the running container

Use the following command to open a interactive shell inside the running container:

docker exec -it f72330919ee5 sh

Replace f72330919ee5 with your actual container ID if it's different.

Step 3: Modify the code inside the container

Once inside the container, open index.js using a text editor like vi or nano.
In the home route, change the response text from:

res.send("Welcome to Home Page");
to:
res.send("Hello World");

Step 4: Commit the running container as a new image

In a new terminal (outside the container), run:

docker commit f72330919ee5

Using the running container ID with docker commit creates a new Docker image from the current state of the running container.

We can tag the newly created image using:

docker tag <new-image-id> <tag-name>

Also, we can change the startup command for the new image by specifying it with -c flag:

docker commit -c 'CMD <new-startup-command>' <new-image-id>

Step 5: Run the new container

Now, run a container from the newly created image using:

docker run -p 5001:8080 <new-image-id or tag>

This will start the container with your modified code.

We can access the modified website at http://localhost:5001

Conclusion

Committing a running container to a new image is a quick way to save changes made inside a container. However, for development purposes, a better approach is to use Docker volumes, which allows us to modify the code on our host machine and see the changes reflected instantly inside the container - without needing to rebuild or commit.