Subnet mask is used to judge any of the two computers belonging to the same IP address is the basis of sub-networks.
Is the most simple to understand their two computers IP address and subnet mask of the AND operation carried out, if the result is the same, this is illustrated in two of Xian contingent τ encyclical TAL-hwan of the oil-缟 shoot the benzene brother Yong-resistant ㄑ> camel饷alcohol equivalent material?
See the following example:
Demonstration of computing: aa
I P address 192.168.0.1
Subnet mask 255.255.255.0
AND computing
Into a binary computing:
I P Address 11010000.10101000.00000000.00000001
Subnet Mask 11111111.11111111.11111111.00000000
AND computing
11000000.10101000.00000000.00000000
After conversion to the metric system:
192.168.0.0
Operational Demonstration bis:
I P address 192.168.0.254
Subnet mask 255.255.255.0
AND computing
Into a binary computing:
I P Address 11010000.10101000.00000000.11111110
Subnet Mask 11111111.11111111.11111111.00000000
AND computing
11000000.10101000.00000000.00000000
After conversion to the metric system:
192.168.0.0
Operational Demonstration three:
I P address 192.168.0.4
Subnet mask 255.255.255.0
AND computing
Into a binary computing:
I P Address 11010000.10101000.00000000.00000100
Subnet Mask 11111111.11111111.11111111.00000000
AND computing
11000000.10101000.00000000.00000000
After conversion to the metric system:
192.168.0.0
Through the above three groups on the computer's IP address and subnet mask AND computing, we can see that it runs is the same. Are 192.168.0.0
Therefore, this computer will be three computer is the same as sub-networks, and then communications. I now use the proxy server units, the internal network is such planning.
Perhaps you have asked such a subnet mask of the number of IP addresses can be used? You can count.
According to the above we can see that the internal LAN ip address is our own provisions (of course, and the other is the same ip address), this is the adoption of a decision by the subnet mask of 255.255.255.0 analysis. Can be drawn:
IP yards from the top three down the figures on the distribution of fixed 192.168.0 So only left on the final one, so obvious, there can be only ip address (2 8-th -1) , 256-1 = 255 for the general bottom of 0 or 255 has its special role.
Then you may want to ask: If my subnet mask 255.255.255.0 not? You can also do so ah suppose your subnet mask is 255.255.128.0
Then your LAN in the two previous ip address is certainly a fixed (what, why is fixed You see upside not to understand? # ￥)
Thus, in accordance with the below you can look at the calculation of the same subnet, in the end to the number of machines
1, the binary decimal 128 = 1000 0000
2, and IP subnet mask code to conduct AND computing
3.
I P Address 00010000.01001001.1 *******.********
Subnet Mask 11111111.11111111.10000000.00000000
AND computing
00010000.01001001.10000000.00000000
After conversion to the metric system:
16 73. 128.0
4, we know the internal network IP address can be used for:
00010000.01001001.10000000.00000000
To
00010000.01001001.11111111.11111111
5, into the metric system:
16.73.128.0 to 16.73.255.255
6,0 and 255 of the Internal usually as a special-purpose network. Do not normally use.
7, the final result was as follows: We all available units for the IP address:
192.168.128.1-192.168.128.254
192.168.129.1-192.168.129.254
192.168.130.1-192.168.130.254
192.168.131.1-192.168.131.254
.......
192.168.139.1-192.168.139.254
192.168.140.1-192.168.140.254
192.168.141.1-192.168.141.254
192.168.142.1-192.168.142.254
192.168.143.1-192.168.143.254
.......
192.168.254.1-192.168.254.254
192.168.255.1-192.168.255.254
8, a total of (255-128 +1) * (254-1 +1) = 128 * 254 = 32512
FAINT !!!!@#!our companies have bought so many can also buy machines? ￥! #
9, see the results are correct
(1), set IP address of 192.168.128.1
Ping 192.168.129.233 pass the test
Visit http://192.168.129.233 can show Home
(2), set IP address of 192.168.255.254
Ping 192.168.129.233 pass the test
Visit http://192.168.129.233 can show Home
10, Conclusion
We concluded that the above is correct. Now you can see your subnet to the number of machines
255.255.255.128
Decomposition:
11111111.11111111.11111111.1000000
So your internal network ip address only
Xxxxxxxx.xxxxxxxx.xxxxxxxx.0 ???????
To
Xxxxxxxx.xxxxxxxx.xxxxxxxx.01111111 |
