子网掩码计算工具，方便网络管理员计算出子网。(Subnet mask calculation tool, which is convenient for network administrators to calculate subnet.)

直接输入需要计算的网络起始段，设定掩码，即可计算各种关联信息。(Directly input the initial segment of the network that needs to be calculated and set the mask to calculate all kinds of correlation information.)