🐧 Setting Up Minimal Debian VM with SSH and Host Integration (Day Log)

📅 Date: July 18, 2025

🧠 Author: admin

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⚙️ Objective

Today’s goal was to set up a minimal Debian virtual machine using VirtualBox with just SSH enabled and then successfully connect to it via the host system’s terminal. The idea was to prepare a lightweight and secure VM that can be controlled entirely via the command line — suitable for future automation, scripting, and Linux-based development.

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📦 Step 1: Installing Debian (Minimal Setup)

• Downloaded Debian ISO (netinst) from the official source.

• Installed Debian on VirtualBox with only openssh-server selected during package configuration.

• No desktop environment, just a clean command-line-based system.

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👤 Step 2: Solving the sudo Issue

Since I didn’t install sudo by default and wasn’t able to run privileged commands, I did the following:

bashCopyEditsu  # Switched to root
apt install sudo
adduser <my_username> sudo

💡 Remember to either log out and log back in, or run newgrp sudo to update group permissions immediately.

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🌐 Step 3: SSH Configuration and Host Linking

✅ Enabled and Started SSH Server

bashCopyEditsudo systemctl enable ssh
sudo systemctl start ssh

✅ Checked IP Address (for bridged/NAT reference)

bashCopyEditip a

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🔁 Step 4: Host ↔ Guest SSH Connection

🎯 Used Port Forwarding:

Since my VM is using NAT networking, I forwarded port 3022 on host to 22 on guest via VirtualBox:

VirtualBox → Settings → Network → Adapter 1 → Advanced → Port Forwarding

🖥️ From Windows Host:

powershellCopyEditssh -p 3022 vbox@127.0.0.1

🛑 Faced a Warning: "REMOTE HOST IDENTIFICATION HAS CHANGED!"

This happened because I had used a similar IP:port combo before, and the SSH fingerprint changed.

Solution:

powershellCopyEditssh-keygen -R [127.0.0.1]:3022

Then retried:

powershellCopyEditssh -p 3022 vbox@127.0.0.1

Connected successfully ✅

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🔐 Step 5: (Optional) Next Steps

Though not done today, I’m planning to:

• Add SSH key login to avoid typing passwords.

• Install virtualbox-guest-utils to enable shared folders.

• Write a bash script for common startup tasks like apt update, ssh start, etc.

• Possibly integrate VS Code using Remote SSH plugin.

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📌 Summary

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