# Accessing Virtual Machine (SSH)

# Generate SSH Key

Here are step-by-step instructions to generate an SSH key on both **Windows** and **Mac** systems:

### For Windows (Windows 10/11):

1. **Ensure OpenSSH Client is Installed**
   - Open **Settings** > **Apps > Apps & Features** > **Optional Features**.
   - Check if **OpenSSH Client** is listed.
   - If not, click **Add a feature**, find **OpenSSH Client**, and install it.
   - Restart your computer if needed.

2. **Open Command Prompt or PowerShell**
   - Press `Windows + R`, type `cmd` or `powershell`, and press Enter.

3. **Generate SSH Key**
   - Type the command:
     ```
     ssh-keygen
     ```
   - Press Enter to accept the default save location (`C:\Users\<username>\.ssh\id_rsa`).

4. **Set a Passphrase (Optional)**
   - When prompted, enter a passphrase for extra security, or just press Enter twice to skip.

5. **Complete**
   - The keys are generated, usually two files: `id_rsa` (private key) and `id_rsa.pub` (public key) under `.ssh` folder in your user directory.

### For Mac (macOS):

1. **Open Terminal**
   - Find Terminal via Spotlight Search or in **Applications > Utilities**.

2. **Generate SSH Key**
   - Run the command, replacing your email with your own:
     ```
     ssh-keygen -t ed25519 -C "your_email@example.com"
     ```
   - If your macOS or server doesn't support Ed25519, use:
     ```
     ssh-keygen -t rsa -b 4096 -C "your_email@example.com"
     ```

3. **Save Key Location**
   - Press Enter to accept the default file location (`/Users/you/.ssh/id_ed25519` or `/Users/you/.ssh/id_rsa`).

4. **Set a Passphrase (Optional)**
   - Enter a secure passphrase or press Enter to leave it blank.

5. **Add SSH Key to ssh-agent**
   - Start the ssh-agent:
     ```
     eval "$(ssh-agent -s)"
     ```
   - Add your private key:
     ```
     ssh-add -K ~/.ssh/id_ed25519
     ```
   - If using RSA:
     ```
     ssh-add -K ~/.ssh/id_rsa
     ```

In both OS, your generated SSH public key is the one you copy and add to services like GitHub, servers, etc. The private key should remain secure and never shared.

# Install Private Key (SSH)

Here are step-by-step instructions on how to **store an SSH private key securely** once generated on both **Windows** and **Mac** systems:

### Windows

1. **Default Location**
   - By default, SSH private keys are saved in your user profile directory under:
     ```
     C:\Users\<your_username>\.ssh\
     ```
   - The private key file is usually named `id_rsa` or similar.

2. **Set File Permissions**
   - Ensure only your user account has access to the private key file:
     - Right-click the private key file > Properties > Security tab.
     - Remove access for any other users or groups except yourself.

3. **Use SSH-Agent for Secure Key Storage**
   - Open **PowerShell as Administrator**.
   - Enable and start the ssh-agent service:
     ```
     Get-Service ssh-agent | Set-Service -StartupType Automatic
     Start-Service ssh-agent
     ```
   - Add your private key to ssh-agent to avoid typing your passphrase every time:
     ```
     ssh-add $env:USERPROFILE\.ssh\id_rsa
     ```
   - The ssh-agent stores your private keys encrypted, protected by your Windows user credentials.

4. **Backup Private Key Securely**
   - Copy the private key file to an **encrypted external drive** or secure **password manager**.
   - Avoid storing private keys in shared or non-encrypted folders.
   - Do NOT share the private key.

### Mac (macOS)

1. **Default Location**
   - Private keys are stored in the hidden `.ssh` folder in your home directory:
     ```
     ~/.ssh/id_rsa
     ```
   - Use `ls -la ~/.ssh` in Terminal to view.

2. **Set Proper File Permissions**
   - Ensure your private key file is readable only by you:
     ```
     chmod 600 ~/.ssh/id_rsa
     ```
   
3. **Add SSH Key to ssh-agent**
   - Start the ssh-agent:
     ```
     eval "$(ssh-agent -s)"
     ```
   - Add your private key with:
     ```
     ssh-add -K ~/.ssh/id_rsa
     ```
   - This stores your key securely in the macOS keychain.

4. **Backup Private Key Safely**
   - Store a copy on an **encrypted USB drive** or a **password manager** like 1Password.
   - Never upload your private key unencrypted to cloud storage.
   - Keep backups separate from your main machine to avoid loss.

**Security best practices:**

- Always protect your private key with a **strong passphrase** when generating it.
- Keep private key files with strict permissions so only your user account can read them.
- Use **ssh-agent** to manage keys in memory instead of repeatedly entering passwords or exposing keys.
- Backup private keys securely and do not share your private keys with anyone.

# Access Virtual Machine (VM) using SSH Key (Windows / Macbook)

Here are step-by-step instructions to access a Server or Virtual Machine using SSH on both **Windows** and **Mac**:

### Windows (Using PowerShell or Command Prompt)

1. **Ensure OpenSSH Client is Installed**
   - Go to **Settings > Apps > Optional Features**.
   - Confirm **OpenSSH Client** is installed; if not, click **Add a feature**, find it, and install.

2. **Open PowerShell or Command Prompt**
   - Press `Windows + R`, type `powershell` or `cmd`, and hit Enter.

3. **Connect via SSH**
   - Use the command:
     ```
     ssh username@server_ip
     ```
   - Replace `username` with your remote server username.
   - Replace `server_ip` with the server’s domain name or IP address.
   - If the server uses a non-standard port, add `-p` followed by the port number:
     ```
     ssh username@server_ip -p port_number
     ```

4. **Verify and Accept Host Key**
   - At first connection, you’ll be asked to verify the server’s fingerprint.
   - Type `yes` and press Enter to continue.

5. **Authenticate**
   - Enter your password when prompted (or if using key authentication, make sure your private key is loaded or specify it with `-i`).

6. **You are connected when your prompt changes to the remote server’s shell.**

### Mac (Using Terminal)

1. **Open Terminal**
   - Use **Spotlight** or find Terminal in **Applications > Utilities**.

2. **Connect via SSH**
   - Type the command:
     ```
     ssh username@server_ip
     ```
   - Substitute `username` and `server_ip` with appropriate remote account and server info.
   - For custom ports, add `-p` option:
     ```
     ssh username@server_ip -p port_number
     ```

3. **Accept Host Key**
   - For the first-time connection, review and accept the host key by typing `yes`.

4. **Authenticate**
   - Enter your password or ensure your SSH private key is loaded (use `ssh-add` if needed).

5. **You are connected once you see the shell prompt of the remote server.**

**Additional Tips:**

- To specify a custom private key file, use the `-i` flag:
  ```
  ssh -i /path/to/private_key username@server_ip
  ```
- To exit the SSH session, type:
  ```
  exit
  ```