Explanation
A sniffer is a tool that captures and analyzes network traffic on a subnet or a network interface. It can help identify the source, destination, protocol, and content of the traffic and detect any anomalies or issues on the network. Verified References: [Sniffer], [Network traffic]

Phishing is a type of attack that is the most difficult to mitigate with technology. Phishing is a technique of deceiving users into revealing their personal or confidential information, such as passwords, credit card numbers, or bank accounts, by sending them fraudulent emails or messages that appear to be from legitimate sources. Phishing relies on human factors, such as curiosity, greed, or fear, to trick users into clicking on malicious links or attachments, or entering their credentials on fake websites. Technology solutions, such as antivirus software, firewalls, or spam filters, can help detect and block some phishing attempts, but they cannot prevent users from falling victim to social engineering tactics. Reference: [CompTIA Server+ Certification Exam Objectives], Domain 5.0: Security, Objective 5.3: Given a scenario, explain methods and techniques to secure data.

The action that the server administrator should take once a new backup scheme has been configured is to run a restore test. A restore test is a process of verifying that the backup data can be successfully recovered and restored to its original location or a different location. A restore test can help ensure that the backup scheme is working properly, that the backup data is valid and consistent, and that there are no errors or issues during the recovery process. A restore test should be performed periodically and after any changes to the backup configuration or environment.