Explanation
A disaster recovery plan would be useful when trying to restore IT infrastructure operations after a non-planned interruption. A disaster recovery plan is a document that outlines the steps and procedures to recover from a major disruption of IT services caused by natural or man-made disasters, such as fire, flood, earthquake, cyberattack, etc. A disaster recovery plan typically includes:
A list of critical IT assets and resources that need to be protected and restored A list of roles and responsibilities of IT staff and stakeholders involved in the recovery process A list of backup and recovery strategies and tools for data, applications, servers, networks, etc.
A list of communication channels and methods for notifying users, customers, vendors, etc.
A list of testing and validation methods for ensuring the functionality and integrity of restored systems A list of metrics and criteria for measuring the effectiveness and efficiency of the recovery process A disaster recovery plan helps IT organizations to minimize downtime, data loss, and financial impact of a disaster, as well as to resume normal operations as quickly as possible.

Reference:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ ch-yum

The HCL stands for Hardware Compatibility List and it is a list of hardware devices that are tested and certified to work with a specific operating system. If a network card is not on the HCL for the OS, it may not function properly or cause compatibility issues. Therefore, verifying the network card is on the HCL for the OS should be the next step to troubleshoot this issue. Reference: https://www.comptia.org/training/resources/exam-objectives/comptia-server-sk0-005-exam-objectives (Objective 4.1)

Explanation
A misconfigured NIC on the server is the most likely reason for the lack of network connectivity. The output of the ping command shows that the server is unable to reach its default gateway (10.0.0.1) or any other IP address on the network. The output of the ipconfig command shows that the server has a valid IP address (10.0.0.10) and subnet mask (255.255.255.0) but no default gateway configured. This indicates that there is a problem with the NIC settings on the server, such as an incorrect IP address, subnet mask, default gateway, DNS server, etc. A misconfigured NIC can also cause an amber link light on the switch port, which indicates a speed or duplex mismatch between the NIC and the switch.

Explanation
A subnet mask is a number that distinguishes the network address and the host address within an IP address1.
A subnet mask allows network traffic to understand IP addresses by splitting them into the network and host addresses. If the subnet mask is incorrect, the network traffic may not be able to determine the correct destination for the packets, and only reach some of the servers that have similar IP addresses. For example, if the new virtual server has an IP address of 192.168.1.100 and a subnet mask of 255.255.0.0, it can only communicate with servers that have IP addresses in the range of 192.168.0.0 to 192.168.255.2552. To fix this issue, the systems administrator needs to check and correct the subnet mask of the new virtual server according to the network configuration.