How do you troubleshoot and debug networks like a pro?

1 Know your network

Before you start troubleshooting and debugging, you need to have a clear understanding of your network topology, architecture, protocols, and devices. This will help you narrow down the scope of the problem, identify the relevant components, and avoid unnecessary steps. You should also document your network configuration, settings, policies, and logs, and keep them updated and accessible. This will save you time and effort when you need to compare the current state with the expected or previous one.

2 Use ping and traceroute

Ping and traceroute are two of the most basic and widely used tools for network troubleshooting and debugging. Ping sends a packet to a destination and measures the time it takes to receive a response. It can help you verify the reachability and latency of a host or device. Traceroute shows the path and hops that a packet takes to reach a destination. It can help you locate the source of a delay, loss, or error in the network. You can use ping and traceroute to test the connectivity and performance of your network from different points and directions.

3 Analyze packets with Wireshark

Wireshark is a powerful and popular tool for network analysis and debugging. It can capture and inspect the packets that flow through your network, and display them in a user-friendly interface. You can use Wireshark to filter, sort, and search the packets by various criteria, such as protocol, source, destination, port, or content. You can also use Wireshark to decode and dissect the packets, and see the details of each layer and field. Wireshark can help you identify and diagnose network issues, such as malformed packets, protocol violations, misconfigurations, or security threats.

4 Monitor network traffic with ntopng

ntopng is a web-based tool for network monitoring and troubleshooting. It can collect and visualize the network traffic data from various sources, such as network interfaces, routers, switches, or probes. You can use ntopng to see the network status, statistics, and trends in real-time or historical mode. You can also use ntopng to drill down into the traffic details, such as hosts, flows, applications, or protocols. ntopng can help you measure and optimize the network performance, bandwidth, and quality of service.

5 Scan network devices with Nmap

Nmap is a versatile and widely used tool for network discovery and security auditing. It can scan and probe the network devices, and provide information about their IP addresses, ports, services, operating systems, versions, and vulnerabilities. You can use Nmap to map out your network topology, inventory your network assets, check your network security posture, and detect any unauthorized or compromised devices. Nmap can also perform advanced tasks, such as port knocking, banner grabbing, or script execution.

6 Debug network applications with curl

curl is a command-line tool for transferring data over various network protocols, such as HTTP, FTP, or SMTP. It can help you debug and test the functionality and behavior of network applications, such as web servers, APIs, or email servers. You can use curl to send and receive requests and responses, and manipulate the headers, methods, parameters, or data. You can also use curl to check the status codes, response times, or redirects of the network applications. curl can help you troubleshoot and debug network issues, such as authentication, encryption, or compression.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?