Network tools are software applications or utilities designed to assist in the management, analysis, monitoring, and troubleshooting of computer networks. These tools are used by network administrators, IT professionals, and system engineers to diagnose network issues, optimize performance, and ensure the security of a network. Here are some common types of network tools:

1. Network Monitoring Tools:
   • Nagios: Monitors hosts, services, and network equipment for availability and performance.
   • Zabbix: Offers real-time monitoring, alerting, and visualization of network data.
   • PRTG Network Monitor: Provides comprehensive network monitoring with customizable dashboards.
2. Packet Analysis Tools:
   • Wireshark: Captures and analyzes network packets to troubleshoot network issues.
   • Tcpdump: A command-line packet analyzer for Unix-like operating systems.
   • Ethereal: An older version of Wireshark (Wireshark was originally named Ethereal).
3. Network Scanning and Discovery Tools:
   • Nmap (Network Mapper): Scans networks for open ports, services, and potential vulnerabilities.
   • Angry IP Scanner: Scans IP addresses and ports to discover devices on a network.
   • Advanced IP Scanner: Scans LANs and provides details about network devices.
4. Bandwidth Monitoring Tools:
   • Cacti: Collects and graphically displays network and system data for bandwidth analysis.
   • SolarWinds Network Performance Monitor: Offers comprehensive bandwidth monitoring and reporting.
   • MRTG (Multi Router Traffic Grapher): Monitors and logs network traffic data.
5. Network Configuration and Management Tools:
   • PuTTY: A versatile SSH and Telnet client for remote server access.
   • OpenSSH: A suite of secure network connectivity tools for remote administration.
   • Cisco Packet Tracer: A network simulation tool for Cisco networking equipment.
6. Firewall Management Tools:
   • pfSense: An open-source firewall and router distribution based on FreeBSD.
   • iptables: A command-line utility for configuring the Linux kernel firewall.
   • Firewall Builder: A graphical firewall configuration and management tool.
7. DNS Tools:
   • nslookup: A command-line tool for querying DNS servers for information.
   • dig (Domain Information Groper): A versatile DNS query tool with advanced options.
   • BIND (Berkeley Internet Name Domain): An open-source DNS server software.
8. Network Security Tools:
   • Snort: An open-source intrusion detection system (IDS).
   • Suricata: An open-source IDS, IPS (Intrusion Prevention System), and network security monitoring tool.
   • Nessus: A vulnerability scanner for identifying security issues in networks.
9. Remote Desktop Tools:
   • Remote Desktop Protocol (RDP): Microsoft’s protocol for remote desktop access.
   • SSH (Secure Shell): Secure remote access and command-line interface.
10. Network Troubleshooting Tools:
    • Ping: Tests network connectivity by sending ICMP echo requests.
    • Traceroute: Diagnoses network path and latency issues by tracing the route packets take.
    • Netstat: Displays active network connections, routing tables, and network interface information.

These tools serve various purposes in network administration, from monitoring and analysis to security and troubleshooting. Network professionals use them to ensure network reliability, performance, and security.