What are the essential network troubleshooting skills that every network engineer should have?

1 Ping and traceroute

Ping and traceroute are two of the most basic and useful network troubleshooting tools. They allow you to test the connectivity and latency between your device and a remote host, and to trace the path and hops that your packets take. Ping sends an echo request to a host and waits for a reply, while traceroute sends a series of packets with increasing TTL (time to live) values and records the response from each router along the way. You can use ping and traceroute to check if a host is reachable, to measure the network performance, and to identify any routing issues or bottlenecks.

2 IP configuration and DNS

IP configuration and DNS are two key components of network communication. IP configuration refers to the settings that enable your device to connect to a network, such as the IP address, subnet mask, gateway, and DHCP server. DNS (domain name system) is the service that translates domain names into IP addresses, and vice versa. You can use various commands and tools to check and troubleshoot your IP configuration and DNS, such as ipconfig, ifconfig, nslookup, and dig. You can use these tools to verify your IP address, to renew or release your DHCP lease, to resolve domain names, and to diagnose any DNS errors or misconfigurations.

3 Network sniffer

A network sniffer is a tool that captures and analyzes the traffic that flows through a network interface. It can help you to monitor the network activity, to inspect the details of each packet, and to identify any anomalies or problems. A network sniffer can be either hardware or software based, and there are many options available, such as Wireshark, tcpdump, and Nmap. You can use a network sniffer to troubleshoot various network issues, such as protocol errors, security breaches, bandwidth utilization, and performance degradation.

4 Port scanner

A port scanner is a tool that scans a host or a range of hosts for open ports. Ports are the logical endpoints of network connections, and each port is associated with a specific protocol or service. A port scanner can help you to discover the services that are running on a host, to check the security posture of a network, and to find any vulnerabilities or misconfigurations. A port scanner can be either active or passive, and there are many options available, such as Nmap, Netcat, and Zenmap. You can use a port scanner to troubleshoot various network issues, such as firewall rules, service availability, and port forwarding.

6 Documentation and communication

Documentation and communication are not technically tools, but they are essential skills for network troubleshooting. Documentation refers to the process of recording and organizing the information about the network, such as the topology, the configuration, the policies, and the incidents. Communication refers to the process of sharing and exchanging the information with the relevant stakeholders, such as the users, the managers, the vendors, and the peers. You can use documentation and communication to troubleshoot various network issues, such as to establish the scope, to follow the procedures, to report the results, and to prevent recurrence.

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?