The default subnet mask for Class C addresses is 255.255.255.0, which means 24 network bits and 8 host bits. To divide six subnets, the network bit must borrow at least three bits of the host bit, and the number of subnets can be divided into three powers of two, that is, eight subnets. Some requirements cannot use all zeros and all 65438+ zeros, so there are only six. Borrowed three bits, the subnet mask is 255.255.255.1100000 (the last octet is written in binary), which is 255.255.224. The subnet is 200.68. 1 92,224), and the host range is the network number of each subnet plus1until the network number of the next subnet is minus 2. That is to say, the host range in each subnet is 1 to 30, 33 to 62 ... 225 to 254 respectively.