10 Essential Tips to Secure Network Layer on Linux Server

☰ In this chapter, you will learn

After securing SSH access to your Linux VPS Server, it's time to secure the network layer. By securing the network layer, you will ensure the protection of your server from network threats and enhance overall server security.

In this article, I will explain 10 useful tips and configurations that will help you protect your server from unauthorized network access.

1 Keep Server Updated

Updating your server is the first step that you should implement periodically to ensure its safety. Keep all installed apps, the server OS, and its kernel updated.

Updating and Upgrading the Ubuntu/CentOS server

2 Firewall Configuration

You must configure the firewall properly to block unauthorized connections to your server. Configure IPTables, Firewalld, and UFW to allow only necessary connections and block others. Don't forget to allow only necessary ports and block unused ports.

IPTables Tutorial: Installing, Configuring, and Managing Firewall on Linux

How do I Setup UFW Firewall on Ubuntu/CentOS

3 Disable Unnecessary Services

Check whether unused services are running in the background. If found, disable them. These unnecessary services not only consume server resources but also provide a surface for attackers to exploit. Attackers are adept at finding vulnerabilities in unused services and may use those vulnerabilities to gain access to your server.

Identify and Disable unnecessary services on Linux Machine

4 Implement SSH Security

This is one of the most crucial steps that you must implement on your VPS server. There are several configurations that must be implemented to protect the SSH server, such as changing the default port (22), configuring key-based access, and disabling root login and password-based login, among others.

Securing SSH/VPS/Linux Server - 27 Tips with Example

5 Monitor Network Access

Also, set up some useful network monitoring tools that can detect suspicious activity in real time and respond accordingly. Tools like Snort or Suricata can assist in intrusion detection.

6 Use VPNs

Use VPNs (Virtual Private Networks) for remote access to your server. It will encrypt the connection and add an extra layer of network security.

7 IP Whitelisting

Only whitelist trusted IP addresses or ranges to access your server or its services. This will secure your server from unauthorized access.

Allow/Block IP address for SSH connections

8 Implement Packet Filtering

There are tools available for packet filtering that can capture and analyze network traffic in real-time. This helps in identifying suspicious activity and blocking them. Use tools like TCPDump or Wireshark to capture and analyze network traffic.

9 Encrypt Network Traffic

Use TLS/SSL to encrypt network traffic. This encrypts transmitted data and helps prevent man-in-the-middle attacks.

10 Regular audit the Log files

Don't forget to audit log files regularly. This will help you analyze suspicious activity and unusual behavior, allowing you to take steps to protect the server.

Monitor your server using auditd

Monitor SSH logs

Conclusion:

In this article, I have explained 10 tips to enhance network security and protect your Linux server from attacks.