Is a default gateway address required on a LAN interface?

A default gateway address is optional on a Local Area Network (LAN) interface because it primarily serves the purpose of routing traffic from one network to another. In a typical LAN setup, devices can communicate with each other directly without needing a gateway if they are within the same subnet. The necessity for a default gateway arises when devices need to communicate outside their local subnet, which is when they would send traffic to a router that connects to other networks.

In scenarios where the LAN operates as a standalone environment or is isolated without needing external communication, configuring a default gateway is not required. Therefore, it is perfectly acceptable to run a LAN interface without a designated default gateway if all devices communicate internally. This flexibility in configuration allows for adaptability based on the network's specific requirements, confirming that a default gateway is indeed optional rather than mandatory.