Internet Protocol Version 4 (IPv4) Practice Test

Understanding broadcast addresses for a given IPv4 block: with a /8 prefix, the subnet mask is 255.0.0.0, so only the first octet defines the network. The network address is when the host portion (the last three octets) is all zeros, which is 10.0.0.0. The broadcast address is when the host portion is all ones, so the last three octets are 255.255.255, giving 10.255.255.255. Therefore, the broadcast address for 10.0.0.0/8 is 10.255.255.255. The other addresses lie within the same 10.x.x.x block but do not have the host portion all ones, so they are not the broadcast address.