CCST Network Troubleshooting & Tools — Questions and Answers
Question 1: What does the 'ping' command test?
- Speed
- Connectivity (Correct answer)
- Security
- Configuration
Correct answer: Connectivity
The 'ping' command is a fundamental network utility primarily used to test the reachability of a host on an Internet Protocol (IP) network. It sends ICMP echo request packets to a target host and listens for ICMP echo reply packets, thereby verifying basic network connectivity between the two devices. While it also measures round-trip time, its core function is to confirm connectivity.
Question 2: What tool traces the route packets take?
- Ping
- Telnet
- Traceroute (Correct answer)
- Netstat
Correct answer: Traceroute
The 'traceroute' (or 'tracert' on Windows) command is a diagnostic tool that maps the path and measures transit delays of packets across an IP network. It identifies all the intermediate routers, or 'hops,' that a packet traverses from the source to the destination. This helps in pinpointing where network latency or connectivity issues might be occurring along the communication path.
Question 3: What command shows active connections?
- Traceroute
- ARP
- Netstat (Correct answer)
- Ping
Correct answer: Netstat
The 'netstat' (network statistics) command-line utility provides comprehensive information about network connections, routing tables, and network interface statistics. It is commonly used to display active network connections (both incoming and outgoing), identify listening ports, and troubleshoot network service issues on a local machine. This makes it invaluable for understanding network activity.
Question 4: What tool resolves IPs to MAC addresses?
- Ping
- NSLookup
- ARP (Correct answer)
- Traceroute
Correct answer: ARP
ARP (Address Resolution Protocol) is a crucial protocol used to resolve IP addresses to MAC (Media Access Control) addresses within a local area network. When a device needs to communicate with another device on the same network segment, it uses ARP to discover the MAC address associated with the target device's known IP address. This mapping is fundamental for data link layer communication.
Question 5: What is used to detect physical connection issues?
- Router
- Cable tester (Correct answer)
- Switch
- Firewall
Correct answer: Cable tester
A cable tester is a specialized hardware tool designed to verify the electrical connection and integrity of network cables, such as Ethernet or fiber optic cables. It can detect common physical connection issues like open circuits, short circuits, crossed pairs, or split pairs. Identifying these physical layer problems is critical for establishing and maintaining a reliable network link.
Question 6: Why use loopback testing?
- Speed test
- Verify port/NIC (Correct answer)
- Software install
- DNS resolution
Correct answer: Verify port/NIC
Loopback testing involves sending data from a device's output back to its input, often using a physical loopback adapter or the special loopback IP address (127.0.0.1). This test is used to verify that the network interface card (NIC) and its associated port are functioning correctly. If the loopback test fails, it indicates a problem with the local hardware, helping to isolate the issue from external network problems.
Question 7: What is a common sign of DNS issue?
- No signal
- Can't access websites (Correct answer)
- Slow typing
- Password error
Correct answer: Can't access websites
A common and frustrating symptom of a DNS issue is the inability to access websites or other network resources by their domain names, even if you can reach them by their direct IP addresses. This occurs because the DNS server is failing to translate the human-readable domain name into the numerical IP address that is required for network communication. The browser simply cannot find the server.
Question 8: What tool shows DNS server responses?
- ARP
- Ping
- NSLookup (Correct answer)
- Traceroute
Correct answer: NSLookup
NSLookup (Name Server Lookup) is a command-line utility specifically designed for querying the Domain Name System (DNS). It allows users to obtain domain name or IP address mappings, as well as other DNS records, directly from DNS servers. This tool is invaluable for diagnosing name resolution problems and verifying DNS configurations.
Question 9: What does ipconfig /all show?
- MAC address only
- Network config (Correct answer)
- Ping stats
- Routing table
Correct answer: Network config
The 'ipconfig /all' command (on Windows operating systems) provides a comprehensive display of all TCP/IP network configuration details for every network adapter on the system. This includes crucial information such as IP addresses, subnet masks, default gateways, MAC addresses, DNS server addresses, and DHCP server information. It is an invaluable tool for diagnosing and troubleshooting network issues.
CCST Network Troubleshooting & Tools
What does the 'ping' command test?