100-160 Question 129
Select 3A user reports that they are unable to access a specific website, and you suspect a DNS resolution issue. Which of the following tools can you use to troubleshoot and diagnose the issue effectively?
- A
netstat
- B
nslookup
- C
tcpdump
- D
traceroute
- E
ping
Show answer and explanation
Correct answers: B, C, E
Explanation
Troubleshooting DNS resolution issues requires tools that can analyze or query DNS behavior. nslookup can directly query DNS servers for records, tcpdump can analyze DNS packets to diagnose issues in real-time, and ping can verify if a domain name resolves to an IP address. netstat and traceroute, while useful for other network-related issues, do not specifically help diagnose DNS resolution problems.
- A. Incorrect.
netstat is primarily used to display active network connections and listening ports, but it does not assist in diagnosing DNS resolution issues.
- B. Correct.
nslookup is specifically designed to query DNS records, making it highly useful for diagnosing DNS resolution issues.
- C. Correct.
tcpdump is a powerful packet analyzer that can capture and analyze DNS queries and responses in real-time, making it a valuable tool for troubleshooting DNS issues.
- D. Incorrect.
traceroute is used to identify the path packets take to a destination, but it does not directly help with DNS resolution diagnostics.
- E. Correct.
ping can help determine whether the domain name resolves to an IP address (indicating successful DNS resolution), making it useful for this scenario.