Learn the complete subnet ranges for IPv4 Class A, B, and C networks. This guide explains default masks, CIDR notation, address ranges, and practical subnetting examples for networking and cybersecurity professionals. IPv4 addressing remains a foundational concept in networking, security engineering, and system administration. Despite the shift toward IPv6, understanding IPv4 subnet ranges and classful addressing is essential for architects, administrators, and analysts working with enterprise networks, firewalls, cloud systems, and compliance-driven environments. This guide provides a clear, structured overview of IPv4 class ranges, default subnet masks, CIDR blocks, and commonly used subnet ranges for Class A, Class B, and…
-
-
Learn how to harden SSH and Access Control Hardening on Ubuntu and openSUSE Linux servers using proven commands, configuration examples, and outputs. Strengthen system security and compliance with best practices for SSH hardening. Key advantages of Access Control Hardening: Comprehensive Access Control Hardening Steps 1. Disable Root Login Root login via SSH is one of the most targeted attack vectors. Disabling root access prevents attackers from brute-forcing the default “root” account. Commands (Ubuntu & openSUSE): Verify: Expected Output: Explanation: This ensures only non-root users can connect. Admins must log in with their personal accounts and use sudo for privileged operations.…