In a situation where a server is installed but not accessible by some clients, which element could be misconfigured?

In the given scenario where a server is installed but not accessible by some clients, a misconfiguration of the default gateway is particularly relevant. The default gateway serves as the path for forwarding packets from one network to another, especially for devices that communicate over different subnets. If the default gateway settings on the server or the clients are incorrect, packets intended for the server might not reach it, resulting in accessibility issues.

Correctly configured default gateways ensure that traffic is properly routed outside a local subnet. If clients are on a different subnet and their default gateway does not point toward the server's subnet, they will be unable to communicate with the server. Thus, confirming that the default gateway is set up correctly can resolve accessibility issues faced by clients trying to reach the server.

While other elements may also affect connectivity, such as the network interface card, firewall settings, and subnet mask, the default gateway specifically plays a critical role in routing traffic in multi-subnet environments. Misconfiguration here is a common source of the accessibility problems described.