Notes on network segment CIDR

Configure settings for the new server today redis Your Internet access is limited to companies ip Address access
CIDR/ The next number indicates that it matches the front ip The length of the address
Such as my ip The address is
112.5.72.133
that
CIDR112.5.72.133/16 That means , Only ip Address before 16 Bit and the address written in the sample 112.5.72.133 Same ip Visit ;
Of course, the digits here refer to Binary system digit
Use... For each paragraph 8 Binary digits represent

give an example
CRID yes
47.146.27.135/13
Convert to binary
…
00101111.10010010.00011011.10000111
take 13 position
00101111.10010
That is, the front of the website 13 The same binary digits can match
This CRID The allowed network segment is
00101111.10010000.00000000.00000000
To
00101111.10010111.11111111.11111111
Convert to decimal
47.144.0.0 To 47.151.255.255