Configuring SSH Access and Security

Tutorial Overview

SSH (Secure Shell) allows secure remote connections to your server. This tutorial covers installation, configuration, and security best practices to protect SSH access.

Prerequisites

• Root or sudo access.

Steps

Step 1: Install the SSH Server

1. Update the package list:

sudo apt update

2. Install the SSH server:

sudo apt install openssh-server -y

3. Check that SSH is running:

sudo systemctl status ssh

• Look for active (running) in the output, which indicates SSH is running.

Step 2: Configure SSH for Security

1. Open the SSH configuration file:bashCopy code

sudo nano /etc/ssh/sshd_config

2. Change the default SSH port (optional but recommended):

• Locate the line #Port 22.
• Uncomment it by removing the # and change 22 to a different port (e.g., Port 2222).

Disable root login over SSH:

• Find the line PermitRootLogin yes.
• Change yes to no to prevent root access:

PermitRootLogin no

3. Allow only specific users to access SSH (optional):

• Add the following line to restrict SSH access to specific users:

AllowUsers your_username

4. Save and close the file.

Step 3: Restart SSH and Test

1. Restart SSH to apply the new settings:

sudo systemctl restart ssh

2. Test the connection from another terminal:

ssh -p <your_new_port> your_username@your_server_ip

3. Check the SSH logs for security auditing:

sudo tail -f /var/log/auth.log

• Watch for unauthorized attempts to access SSH and investigate as needed.