This is the most likely cause of the user's connection issues, because the ARP table of the switch shows that there are two devices with the same IP address of 192.168.1.10, but different MAC addresses. This indicates that there is an IP address conflict on the network, where two devices are trying to use the same IP address.
This can cause intermittent connectivity issues, as the switch may not be able to forward packets to the correct destination .

A 'crossover cable' is a type of Ethernet cable that has two ends with reversed wiring. This means that the transmit pins on one end are connected to the receive pins on the other end. This type of cable is used to directly connect two similar devices, such as two switches, without the need for a hub or a router.

Explanation
The nslookup command should be run to confirm the server name for all Linux servers. Nslookup is a tool that queries DNS servers to resolve hostnames to IP addresses or vice versa. It can also provide other information about DNS records, such as MX, NS, SOA, etc. By running nslookup with the IP address of a Linux server, the technician can obtain its hostname. References:
https://www.howtogeek.com/663056/how-to-use-the-nslookup-command-on-linux/

Network traffic is the amount of data moving across a computer network at any given time. Network traffic is broken down into data packets and sent over a network before being reassembled by the receiving device or computer1.
Network traffic has two directional flows, north-south and east-west. North-south traffic refers to client-to-server traffic that moves between the data center and the rest of the network (i.e., a location outside of the data center). East-west traffic refers to traffic within a data center, also known as server-to-server traffic12.
A data center is a facility that houses computing and networking equipment, such as servers, switches, routers, firewalls, and storage devices. Data centers provide centralized processing, storage, and access to data and applications for organizations and users3.
Data centers need to handle both north-south and east-west traffic efficiently and securely. North-south traffic is typically generated by users or customers who access data or applications hosted in the data center from the internet or other networks. East-west traffic is typically generated by applications or services that communicate with each other within the data center.
The question asks which of the following describes traffic going in and out of a data center from the internet. The correct answer is B. North-South, because this is the type of traffic that flows between the data center and the external network. The other options are incorrect for the following reasons:
A . Demarcation point is the physical point where the responsibility for the network changes from one party to another, such as from a service provider to a customer. It does not describe network traffic.
C . Fibre Channel is a high-speed network technology that connects servers and storage devices in a data center. It does not describe network traffic, but rather a network protocol.
D . Spine and leaf is a network topology that consists of two layers of switches: spine switches that interconnect with leaf switches, and leaf switches that connect to servers and devices. It does not describe network traffic, but rather a network design. Reference:
1: What Is Network Traffic? Definition and How To Monitor It
2: 32 Flashcards | Quizlet
3: Data center - Wikipedia
4: Data Center Traffic Patterns: North-South vs. East-West
5: Demarcation point - Wikipedia
6: Fibre Channel - Wikipedia
7: Spine and leaf - Wikipedia

Explanation
Port 53 is used for DNS, which is a service that translates domain names into IP addresses. Port 995 is used for POP3S, which is a protocol for receiving email messages securely. POP3S supports large file transfers and encryption. Therefore, these two ports should be opened for the mail server and the DNS server project