What are two most popular network operating systems?

1. Windows Server - Developed by Microsoft, Windows Server is a popular network operating system used by many businesses and organizations. It provides various features and services, including file and print sharing, authentication, networking, virtualization, and remote access.

2. Red Hat Enterprise Linux (RHEL) - RHEL is an enterprise-grade Linux distribution developed by Red Hat. It provides a highly stable and reliable environment for mission-critical applications. RHEL offers numerous features and services for network management, system security, virtualization, and software development.