Generate IPv4 subnetting problems, work out the network and broadcast addresses, find the usable host range and check your answer. If you get stuck, Baznetic will walk through the calculation step by step.
A subnet mask separates the network portion of an IPv4 address from the host portion. For CCNA questions, you will commonly need to identify the subnet boundary, broadcast address and usable host range.
Convert the CIDR prefix, such as /27, into its subnet mask. A /27 is 255.255.255.224.
Find the interesting octet and subtract its mask value from 256. For 224, the block size is 32.
Locate the block containing the IP address. The first address is the network address and the final address is the broadcast address.