Network+ Troubleshooting Tools and Methods Flashcards

A network technician is troubleshooting a connectivity issue. After identifying the problem, they believe the issue is related to a faulty DNS configuration. According to the CompTIA troubleshooting methodology, what is the IMMEDIATE next step?

Answer: Test the theory to determine the cause.

The CompTIA troubleshooting methodology follows a specific order: 1. Identify the problem. 2. Establish a theory of probable cause. 3. Test the theory to determine the cause. 4. Establish a plan of action. 5. Implement the solution. 6. Verify full system functionality. 7. Document findings. After establishing a theory (a faulty DNS configuration), the next logical step is to test that theory, for example, by using `nslookup` or changing to a known-good DNS server.

A technician needs to identify a specific network cable within a large, unlabeled bundle of cables in a wiring closet. Which of the following tools is BEST suited for this task?

Answer: Toner generator and probe

A toner generator and probe is specifically designed for this purpose. The tone generator is attached to one end of the cable, sending a signal along the wire. The inductive probe is then used at the other end to detect that signal audibly, allowing the technician to identify the correct cable without direct electrical contact.

A user reports slow access to a remote server. A network administrator wants to identify the specific router in the path that is causing high latency. Which command-line utility should the administrator use?

Answer: tracert

The `tracert` (or `traceroute` on Linux/macOS) command is designed to map the path that packets take to a destination. It shows the round-trip time to each 'hop' (router) along the way, making it ideal for pinpointing where delays or packet loss are occurring in the network path. `ping` only shows the final round-trip time, `netstat` shows active connections, and `ipconfig` shows local IP configuration.

A technician is troubleshooting a potentially faulty network interface card (NIC) on a workstation. To test if the NIC can successfully send and receive data without connecting to the live network, which tool should be used?

Answer: Loopback adapter

A loopback adapter is a special plug that connects the transmit (Tx) pins to the receive (Rx) pins on a network port. This allows the NIC to send a signal and immediately receive it back, creating a 'loop'. This test verifies the functionality of the port's internal circuitry without needing a connection to a switch or another device.

A network administrator runs a command-line utility and receives an output that lists active TCP and UDP connections, listening ports, and the executables using those connections. Which of the following commands was MOST likely used?

Answer: netstat -anb

The `netstat` (network statistics) command is used to display network connections, routing tables, and interface statistics. The `-a` flag shows all active TCP and UDP connections and listening ports, `-n` displays addresses and port numbers numerically, and the `-b` flag (on Windows) shows the executable involved in creating each connection or listening port.

A help desk technician receives a call from a user who cannot access `www.comptia.org` by its domain name but can access it by its IP address. This indicates a likely problem with DNS resolution. Which command-line tool would be most effective for diagnosing this specific issue?

Answer: nslookup

`nslookup` (or `dig`) is a command-line tool specifically designed to query the Domain Name System (DNS) to obtain domain name or IP address mapping information. Since the user can reach the site by IP, connectivity is confirmed, but name resolution is failing. `nslookup` can be used to query the configured DNS server and see why it is failing to resolve the hostname.