Network tools refer to a category of software applications or utilities designed to help users manage, analyze, troubleshoot, and optimize computer networks. These tools play a crucial role in maintaining the health and performance of network infrastructure. Here are some common functionalities provided by network tools:

1. Network Monitoring:
   • Purpose: Monitor the performance and status of network devices and services in real-time.
   • Examples: Wireshark, Nagios, SolarWinds.
2. Network Scanning:
   • Purpose: Identify and map devices connected to a network, discover open ports, and assess vulnerabilities.
   • Examples: Nmap, Angry IP Scanner.
3. Packet Sniffing:
   • Purpose: Capture and analyze data packets flowing through a network for troubleshooting or security analysis.
   • Examples: Wireshark, tcpdump.
4. Bandwidth Analysis:
   • Purpose: Measure the amount of data that can be transmitted over a network connection and identify bandwidth usage patterns.
   • Examples: iperf, NetFlow analyzers.
5. Ping and Traceroute:
   • Purpose: Test the reachability of a host on an Internet Protocol (IP) network and determine the route packets take to reach the destination.
   • Examples: Ping, traceroute, MTR (My TraceRoute).
6. Network Configuration Management:
   • Purpose: Track changes in network configurations, backup configurations, and maintain consistency across devices.
   • Examples: RANCID, SolarWinds Network Configuration Manager.
7. Firewall and Security Analysis:
   • Purpose: Evaluate the security of a network by analyzing firewall rules, intrusion detection/prevention systems, and security policies.
   • Examples: Nessus, Snort.
8. DNS Tools:
   • Purpose: Resolve domain names to IP addresses, troubleshoot DNS-related issues, and perform DNS lookups.
   • Examples: nslookup, dig.
9. Remote Administration:
   • Purpose: Manage and configure network devices remotely.
   • Examples: SSH (Secure Shell), Telnet.
10. Network Simulation:
    • Purpose: Create virtual network environments for testing and training without affecting the production network.
    • Examples: Cisco Packet Tracer, GNS3.

These tools collectively assist network administrators and engineers in ensuring the reliability, security, and optimal performance of computer networks. They are valuable for diagnosing problems, planning network expansions, and maintaining the overall health of network infrastructure.