An administrator replaces the network card in a web server. After replacing the network card some users can access the server but others cannot. Which of the following is the FIRST thing the administr

Inconsistent access to a web server after a network card replacement often indicates a problem with the server's IP configuration, specifically its default gateway. If the default gateway is incorrect, the server cannot route traffic to networks outside its local subnet, leading to connectivity issues for remote users while local users might still connect.

Vague checks of 'the ports on the switch' would usually lead to complete loss of connectivity for the server, not partial or inconsistent access from specific user groups.

Port security, if misconfigured or triggered by a new MAC address, would completely block all traffic from the server, resulting in no connectivity rather than some users being able to access it.

A faulty Ethernet cable would result in no network connectivity for the server, or extremely intermittent and complete drops, not a pattern where some users can reliably connect while others cannot.