1. Wireshark – Packet Analyzer

Wireshark is one of the most popular open-source packet analyzers. It allows you to capture and analyze real-time network traffic to diagnose issues such as latency, packet drops, and suspicious activity.

Best For: Deep packet inspection, troubleshooting network problems, and learning protocols.

2. Nmap – Network Scanner

Nmap (Network Mapper) is a free tool that scans networks to discover devices, open ports, and running services. IT admins use it for security auditing and network inventory.

Best For: Network discovery, port scanning, and vulnerability assessment.

3. Angry IP Scanner

Angry IP Scanner is a lightweight tool that quickly scans IP addresses and ports. It’s easy to use and great for small office or home networks.

Best For: Detecting connected devices and checking network availability.

4. PuTTY – SSH and Telnet Client

PuTTY is a free SSH and Telnet client used to connect remotely to Linux and networking devices. IT admins use it daily for configuration and management.

Best For: Remote management of servers, routers, and switches.

5. Netcat – The Swiss Army Knife of Networking

Netcat (nc) is a versatile command-line tool that can read and write data across TCP/UDP connections. It’s often used for debugging, testing, and scripting network operations.

Best For: Debugging, port listening, and quick network testing.