Explanation
The command iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination
192.0.2.25:3128 adds a rule to the nat table that redirects all incoming TCP packets with destination port 80 (HTTP) to the proxy server 192.0.2.25 on port 3128. This is the correct way to achieve the task. The other options are incorrect because they either delete a rule (-D), use the wrong protocol (top instead of tcp), or use the wrong port (81 instead of 80). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 381.

Explanation
The correct answer is A. semanage port -a -t ssh_port_t -p tcp 2222
This command will allow the SSH server to bind to port 2222 by adding it to the SELinux policy. The semanage command is a utility for managing SELinux policies. The port subcommand is used to manage network port definitions. The -a option is used to add a new record, the -t option is used to specify the SELinux type, the -p option is used to specify the protocol, and the tcp 2222 argument is used to specify the port number. The ssh_port_t type is the default type for SSH ports in SELinux.
The other options are incorrect because:
B: chcon system_u:object_r:ssh_home_t /etc/ssh/*
This command will change the SELinux context of all files under /etc/ssh/ to system_u:object_r:ssh_home_t, which is not correct. The ssh_home_t type is used for user home directories that are accessed by SSH, not for SSH configuration files. The correct type for SSH configuration files is sshd_config_t.
C: iptables -A INPUT -p tcp --dport 2222 -j ACCEPT
This command will add a rule to the iptables firewall to accept incoming TCP connections on port 2222.
However, this is not enough to fix the issue, as SELinux will still block the SSH server from binding to that port. Moreover, iptables may not be the default firewall service on some Linux distributions, such as Fedora or CentOS, which use firewalld instead.
D: firewall-cmd --zone=public --add-port=2222/tcp
This command will add a rule to the firewalld firewall to allow incoming TCP connections on port 2222 in the public zone. However, this is not enough to fix the issue, as SELinux will still block the SSH server from binding to that port. Moreover, firewalld may not be installed or enabled on some Linux distributions, such as Ubuntu or Debian, which use iptables instead.
References:
How to configure SSH to use a non-standard port with SELinux set to enforcing Change SSH Port on CentOS/RHEL/Fedora With SELinux Enforcing How to change SSH port when SELinux policy is enabled

Explanation
The Linux administrator should request the following types of DNS records from the DNS team:
A: This record type is used to map a hostname to an IPv4 address. The administrator needs four A records for devel.comptia.org, one for each IP address (5.5.5.1, 5.5.5.2, 5.5.5.3, 5.5.5.4). This will allow users to access the web servers by using the hostname devel.comptia.org instead of the IP addresses1.
CNAME: This record type is used to create an alias for another hostname. The administrator needs two CNAME records, one for dev.comptia.org and one for development.comptia.org, both pointing to devel.comptia.org. This will allow users to access the web servers by using any of these three hostnames interchangeably1.
NS: This record type is used to delegate a domain or a subdomain to another name server. The administrator needs one NS record for comptia.org, pointing to 5.5.5.254, which is the name server that hosts the records for the subdomain devel.comptia.org2. This will allow users to resolve the hostnames under comptia.org by querying the name server 5.5.5.2542.
The other record types are not relevant for the administrator's task:
MX: This record type is used to specify the mail exchange server for a domain or a subdomain1. The administrator does not need this record type because the web servers are not intended to handle email traffic.
PTR: This record type is used to map an IP address to a hostname, which is the reverse of an A record1.
The administrator does not need this record type because the web servers are not expected to be accessed by their IP addresses.
RRSIG: This record type is used to provide digital signatures for DNSSEC, which is a security extension for DNS that verifies the authenticity and integrity of DNS responses3. The administrator does not need this record type because it is not mentioned in the task requirements.
SOA: This record type is used to provide information about the authoritative name server and other parameters for a domain or a subdomain1. The administrator does not need this record type because it is usually created automatically by the name server software when a new zone file is created4.
TXT: This record type is used to store arbitrary text data that can be used for various purposes, such as SPF, DKIM, DMARC, etc1. The administrator does not need this record type because it is not related to the web server functionality.
SRV: This record type is used to specify the location and port number of a service that runs on a domain or a subdomain1. The administrator does not need this record type because the web servers use the standard HTTP port 80, which does not require an SRV record.
References: 1: DNS Record Types - CompTIA Network+ N10-007 - 1.8 2: NS Record - DNSimple Help 3:
DNSSEC - Wikipedia 4: SOA Record - DNSimple Help

Explanation
The user1 password is expired. This can be inferred from the output of the chage -l user1 command, which shows the password expiration information for user1. The output shows that the password expired on
2020-10-01, and the account expired on 2020-10-08. This means that user1 cannot log in to the server unless the password and account are reactivated by the system administrator.
The other options are not correct based on the outputs above. User1 does not need to set a long password, because the output of the passwd -S user1 command shows that the password has a minimum length of 5 characters, which is met by user1's password. User1 is not in the incorrect group, because the output of the groups user1 command shows that user1 belongs to the app group, which is presumably the correct group for accessing the server. The user1 shell assignment is not incorrect, because the output of the grep user1
/etc/passwd command shows that user1 has /bin/bash as the default shell, which is a valid and common shell for Linux users.

Explanation
The command systemct1 status systemd-resolved.service will show the information about the service systemd-resolved.service. The systemct1 command is a tool for managing system services and units.
The status option displays the current status of a unit, such as active, inactive, or failed. The output also shows the unit description, loaded configuration, process ID, memory usage, and recent log messages. This command will show if the service systemd-resolved.service is running without any errors. This is the correct command to use to accomplish the task. The other options are incorrect because they either perform different actions (enable, mask, or show) or do not show the status of the service (systemct1 show systemd-resolved.service only shows the properties of the service, not the status). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes and Scheduling Tasks, page
427.