A PC with IP 192.168.1.2 has a static ARP on the gateway. If the Ethernet card fails and is replaced, what needs to be done?

When a PC with a static ARP entry for a gateway has its Ethernet card replaced, the correct action is to update the static ARP entry. A static ARP entry binds an IP address to a specific MAC address. When the Ethernet card fails and is replaced, it will have a new MAC address which means the existing static ARP entry will no longer be valid.

By updating the static ARP entry with the new MAC address associated with the replaced Ethernet card, the PC will be able to properly communicate with the gateway again. This is critical for ensuring that the routing of data packets to the correct destination occurs seamlessly.

For reference, the other options do not address the need for adjusting the ARP table. Simply leaving it as is may lead to communication failures, while changing the MAC address to the old card's value would not work since the old hardware is no longer present. Adding another IP for Internet access could allow for connectivity in some scenarios, but it would not resolve the issue of the static ARP entry becoming obsolete due to the hardware change.