The most efficient subnet address for a network that will have no more than 30 available IP addresses is
255.255.255.224. This subnet mask corresponds to a /27 prefix length, which means that 27 bits are used for the network portion and 5 bits are used for the host portion of an IP address. With 5 bits for hosts, there are
2^5 - 2 = 30 possible host addresses per subnet, which meets the requirement. The other options are either too large or too small for the network size. Reference: https://www.ibm.com/cloud/learn/subnet-mask

The access control methodology that can be described best as allowing a user the least access based on the jobs the user needs to perform is role-based access control (RBAC). RBAC is an access control method that assigns permissions to users based on their roles or functions within an organization. RBAC provides fine-grained and manageable access control by defining what actions each role can perform and what resources each role can access. RBAC follows the principle of least privilege, which means that users are only granted the minimum level of access required to perform their tasks. RBAC can reduce security risks, simplify administration, and enforce compliance policies.

A DNS entry is a record that maps a domain name to an IP address. If the DNS entry for the new application is incorrect, users will not be able to resolve the domain name to the correct IP address and port number. This will prevent them from accessing the application, even if the firewall rules allow port 8443. To fix this issue, the server administrator should verify and update the DNS entry for the new application.
References: CompTIA Server+ Study Guide, Chapter 6: Networking, page 230.

Since both drives are in different RAID 1 arrays and both are hot-swappable, the most efficient step is to replace both failed drives at the same time. This can minimize the downtime and avoid unnecessary reboots.
RAID 1 provides mirroring, which means that data is duplicated on both drives in the array. Therefore, replacing one drive will not affect the data on the other drive or the functionality of the array. References:
https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_1

If the server administrator patches the server with the latest vendor-suggested software, configures DHCP, and verifies all network cables are properly connected in the IDF, but there is no network connectivity, then the most likely reason for the lack of connectivity is that the VLAN is improperly configured. A VLAN (Virtual Local Area Network) is a logical grouping of network devices that share the same broadcast domain and can communicate with each other without routing. If the server is assigned to a different VLAN than the DHCP server or the default gateway, it will not be able to obtain an IP address or reach other network devices.
The DNS configuration is not relevant for network connectivity, as DNS only resolves names to IP addresses.
The OS version is not likely to be incompatible with the network switch vendor, as most network switches use standard protocols and interfaces. The HIDS (Host-based Intrusion Detection System) is not likely to prevent the connection, as HIDS only monitors and alerts on suspicious activities on the host. References:
https://www.howtogeek.com/190014/virtualization-basics-understanding-techniques-and-fundamentals/
https://www.howtogeek.com/164981/how-to-use-nslookup-to-check-domain-name-information-in-microsoft- windows/ https://www.howtogeek.com/202794/what-is-an-intrusion-detection-system-ids-and-how-does-it- work/