A network administrator is adding a new LAN to a branch office that needs to support 4 connected devices. What is the smallest network mask they can use?

The smallest network mask that can support 4 connected devices is 255.255.255.252. This subnet mask allows for a total of 4 IP addresses, out of which 2 are usable for host devices, while the other two are reserved for network and broadcast addresses.

Using the CIDR notation, 255.255.255.252 corresponds to a /30 prefix. In this scenario, with 4 total addresses (2 usable for hosts), it’s suitable for scenarios where only a small number of devices need to be connected. This makes it ideal for point-to-point connections or small subnets that require minimal address allocation while efficiently utilizing IP space.

In contrast, the other network masks provide a larger number of available addresses than needed. For instance, 255.255.255.0 (or /24) provides 256 addresses, including many extra addresses that would not be used in this specific instance. Similarly, 255.255.255.248 (or /29) gives 8 addresses (6 usable), and 255.255.255.128 (or /25) supplies 128 addresses (126 usable), both of which far exceed the requirement for only 4 devices. Therefore, using the /