What does the subnet mask reveal about an IPv4 address?

• A. It reveals which part is the network portion and which part is the host portion.
• B. It reveals the device's hardware address.
• C. It reveals the default gateway.
• D. It reveals the maximum packet size.

Answer: (C)

Subnet masks define which bits of an IPv4 address belong to the network portion and which bits belong to the host portion. This division lets devices and routers determine if a destination is on the same local network or if traffic should be sent to a gateway to reach another network. For example, with an address like 192.168.1.10 and a mask of 255.255.255.0, the network part is 192.168.1.x and the host part is the final octet, 10 in this case.

This mask does not reveal the device’s hardware (MAC) address, the default gateway, or the maximum packet size (MTU). The gateway is a separate router address used for routing to other networks, and MTU is about how large a packet can be.