a：177.0.0.0，
b：95.3.0.0，
c：127.190.0.0，
d：255.128.0.0。
2) The subnet mask is 255255.255.What does 0 mean?
3) How many types of IP addresses are there?
1) The subnet mask is recommended to use the mask of consecutive 1 and consecutive 0, in the subnet mask of ABCD, write it as binary, and find that only D is a mask of consecutive 1 and consecutive 0, which is recommended. (6 points).
2) There are 3 meanings:
For the IP address of a Class A network, the first 8 digits represent the network number, and the last 24 digits represent the host number, using the subnet mask 255255.255.0 indicates that the first 8 digits are the network number, the middle 16 bits are used to divide the subnet segment, and the last 8 bits are the host number.
The second type is a Class B network, for the IP address of the Class B network, the first 16 bits represent the network number, the last 16 bits represent the host number, and the subnet mask 255 is used255.255.0 indicates that the first 16 bits are the network number, the middle 8 bits are used to divide the subnet segment, and the last 8 bits are the host number.
The third type is a Class C network, and this subnet mask is the default subnet mask of the Class C network.
3) IP addresses are classified into ABCDE 5 categories;