The IP address/default gateway combination that the administrator should have used for the new server is IP address: 192.168.10.2/24 and Default gateway: 192.168.10.1. The IP address and the default gateway of a device must be in the same subnet to communicate with each other. A subnet is a logical division of a network that allows devices to share a common prefix of their IP addresses. The subnet mask determines how many bits of the IP address are used for the network prefix and how many bits are used for the host identifier. A /24 subnet mask means that the first 24 bits of the IP address are used for the network prefix and the last 8 bits are used for the host identifier. Therefore, any IP address that has the same first 24 bits as the default gateway belongs to the same subnet. In this case, the default gateway has an IP address of 192.168.10.1/24, which means that any IP address that starts with 192.168.10.x/24 belongs to the same subnet. The new server has an IP address of 192.168.1.1/24, which does not match the first 24 bits of the default gateway, so it belongs to a different subnet and cannot communicate with the default gateway. To fix this issue, the administrator should change the IP address of the new server to an unused IP address that starts with 192.168.10.x/24, such as
192.168.10.2/24.