Which Tool Identifies Open Ports on a Remote Server?

N10-009 By islever Editorial Last updated Sep 3, 2026

Short answer

B nmap

Question

A user notifies a network administrator about losing access to a remote file server. The network administrator is able to ping the server and verifies the current firewall rules do not block access to the network fileshare. Which of the following tools would help identify which ports are open on the remote file server?

dig
nmap Correct Answer
tracert
nslookup

Key Takeaways

The question tests knowledge of common network utilities, specifically nmap's port-scanning capability, while distractors like dig and nslookup focus on DNS resolution.

For the CompTIA Network+ N10-009 exam, nmap is the correct tool to identify open ports on a remote file server. Community consensus strongly supports option B.

Common mistake: Choosing dig, nslookup, or tracert, because although they are network troubleshooting tools, they do not scan for open ports; nmap is the only port scanner listed.

Expert Analysis

Why the Answer Is Correct

Nmap (Network Mapper) is specifically designed to discover hosts and services on a computer network by sending packets and analyzing responses. It can identify which ports are open, closed, or filtered on a remote server, making it the right tool when a user can ping the server but fileshare access fails. Community comment [1] correctly notes nmap scans ports and can be used legitimately or maliciously.

Why the Other Options Are Wrong

dig and nslookup are DNS lookup utilities used to query name servers for domain name and IP address information; they do not scan ports. tracert (traceroute) traces the network path packets take to a destination, which can show routing hops but not open ports on the destination server. None of these tools provide information about which ports are listening on the remote file server.

Community Comment Notes

All commenters choose B, confirming the clear consensus. Comment [2] mistakenly describes a "network map" rather than nmap, but still selects the correct answer. Comment [3] reinforces that nmap is the most appropriate tool for identifying open ports. Ignore the inaccurate explanation in comment [2] and focus on nmap's port-scanning function.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

Remember that nmap is the go-to for port scanning, while dig and nslookup are DNS tools and tracert is a path-tracing tool. When a question asks about open ports or service enumeration, nmap is almost always the intended answer.

Community Votes

100%

100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 3

BobbyCruz111 👍 3 Answered B

NMAP- It will allow for scanning of ports that are open. Great tool for listening and can be used for malicious purposes as well.
HeatSquad77 👍 1 Answered B

B. network map A highly detailed illustration of a network, down to the individual computers. A network map shows IP addresses, ports, protocols, and more.
chupapi_001 👍 1 Answered B

The correct answer is B. nmap Nmap (Network Mapper) is the most appropriate tool for identifying open ports on the remote file server.

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