A user notifies a network administrator about losing access to a remote file server.

nmap is the tool that would help identify which ports are open on the remote file server. nmap stands for Network Mapper, which is a free and open-source tool that can perform various network scanning and discovery tasks. nmap can help identify which ports are open on a remote device by sending probes or packets to different ports and analyzing the responses. nmap can also provide information about the operating system, services, versions, firewalls, or vulnerabilities of the remote device. nmap can be useful for network administrators, security professionals, or hackers to monitor, audit, or attack network devices. References: [CompTIA Network+ Certification Exam Objectives], Nmap - Free Security Scanner For Network Exploration & Security Audits