In IP subnetting, which statement is true?

In IP subnetting, which statement is true?

• A. Every device must have the same subnet.
• B. It uses a subnet mask to delineate the network vs host portions.
• C. Subnetting eliminates the need for DNS.
• D. Subnetting reduces network efficiency.

Answer: (B)

Subnet masks tell you which part of an IPv4 address identifies the network and which part identifies a host within that network. The mask has 1s for the network bits and 0s for the host bits, so when you combine an IP with its mask, you can determine the destination network and whether a target is local or must be routed elsewhere. For example, with 192.168.1.10 and a 255.255.255.0 mask, the network is 192.168.1.0 and the host portion is 10, meaning this device sits on the 192.168.1.0/24 subnet. That’s why the statement about every device needing the same subnet isn’t correct—networks can be partitioned into multiple subnets, and devices on different subnets communicate via routers. Subnetting also doesn’t remove DNS; DNS is still needed to translate names to IP addresses. And subnetting doesn’t reduce network efficiency; it typically improves efficiency by reducing broadcast domains and organizing routing, not the opposite.

Subnet masks tell you which part of an IPv4 address identifies the network and which part identifies a host within that network. The mask has 1s for the network bits and 0s for the host bits, so when you combine an IP with its mask, you can determine the destination network and whether a target is local or must be routed elsewhere. For example, with 192.168.1.10 and a 255.255.255.0 mask, the network is 192.168.1.0 and the host portion is 10, meaning this device sits on the 192.168.1.0/24 subnet.

That’s why the statement about every device needing the same subnet isn’t correct—networks can be partitioned into multiple subnets, and devices on different subnets communicate via routers. Subnetting also doesn’t remove DNS; DNS is still needed to translate names to IP addresses. And subnetting doesn’t reduce network efficiency; it typically improves efficiency by reducing broadcast domains and organizing routing, not the opposite.