Network troubleshooting and detection commands

Network troubleshooting and detection are core skills in system operation and maintenance and network management. To quickly locate and resolve issues such as network latency, packet loss, route interruptions, or port outages, administrators need to utilize a series of classic command-line tools. This chapter will detail the practical usage and output interpretation of commands such as ping, traceroute/tracert, netstat, nslookup, telnet, tcpdump, and curl. By combining the detection logic of these commands with common fault characteristics, readers can establish a systematic troubleshooting approach from the physical link to the application layer, thereby efficiently diagnosing and restoring services in complex network environments.