CompTIA Server+ SK0-005 Release Date

The most likely cause of the internet issue is B. The DHCP scope is full.

A DHCP scope is a range of IP addresses that a DHCP server can assign to DHCP clients on a network. A DHCP scope has a start address and an end address, and it can also have some excluded addresses that are not available for lease. A DHCP scope can have various options, such as subnet mask, default gateway, DNS server, etc., that are applied to the DHCP clients along with the IP address. A DHCP scope also has a lease time, which is the duration that a DHCP client can use an IP address before renewing it or releasing it. A DHCP scope can have reservations, which are fixed IP addresses that are assigned to specific DHCP clients based on their MAC addresses12

If a DHCP scope is full, it means that there are no more IP addresses available for lease in the scope. This can happen if the number of DHCP clients exceeds the number of IP addresses in the scope, or if the lease time is too long and the IP addresses are not released or reused frequently enough. If a DHCP scope is full, any new or existing DHCP clients that request an IP address from the DHCP server will not receive one, and they will not be able to access the network or the internet12

In this scenario, users are able to connect to the wireless network, but they are unable to access the internet. The network administrator verifies connectivity to all network devices, and there are no ISP outages. The server administrator removes the old address leases from the active leases pool, which allows users to access the internet. This indicates that the DHCP scope is full, and that removing the old leases frees up some IP addresses for lease in the scope. Therefore, option B is the most likely cause of the internet issue.

Port 21 is used for FTP (File Transfer Protocol), which is a protocol that transfers files between servers and clients in cleartext, meaning that anyone can intercept and read the data. To stop this communication, port 21 should be closed on the web server and replaced with a secure protocol, such as SFTP (Secure File Transfer Protocol) or FTPS (File Transfer Protocol Secure), which use encryption to protect the data. Verified References: [FTP vs SFTP vs FTPS]

Round robin is a load balancing technique that distributes requests among multiple web nodes in a circular order. It ensures that each web node receives an equal amount of requests and improves the availability and performance of the web application. Verified References: [Round robin], [Load balancing]

A DHCP reservation is a way to assign a specific IP address to a device based on its MAC address, which is a unique identifier for each network interface card (NIC). When the administrator replaced the NIC, the MAC address of the server changed, and the DHCP server no longer recognized it as the same device. Therefore, the DHCP server assigned a different IP address to the server, which was incorrect for the application. To fix this problem, the administrator needs to modify the DHCP reservation to use the new MAC address of the NIC, so that the server can get the proper IP address.

A WWNN (World Wide Node Name) is a unique identifier for a Fibre Channel node, which is a device that can communicate over a Fibre Channel network. A WWNN is not related to DHCP or IP addresses, and it is not used for DHCP reservations. Therefore, options B and D are incorrect.

Updating the local hosts file with the correct IP address (option C) is also incorrect, because it does not solve the problem of getting the correct IP address from the DHCP server. The hosts file is a local file that maps hostnames to IP addresses, and it is used to override DNS queries. However, it does not affect how the DHCP server assigns IP addresses to devices. Moreover, updating the hosts file manually on every device that needs to communicate with the server is not a scalable or efficient solution.

References:

How to reserve IP Address in DHCP Server - Ask Ubuntu

Static IP vs DHCP Reservation - The Tech Journal

How to Configure DHCP Server Reservation in Windows … - ITIngredients