Appendix I - Cipafilter Documentation

Manual - Appendix I: Dot notation to CIDR notation translation table

The following table shows how to convert common dot-notation subnet masks to CIDR-notation subnet bits.

As an example: The subnet mask 255.255.0.0 , when applied to 172.16.0.0 , will cover the addresses 172.16.0.0 172.16.255.255 .  To refer to this same range of addresses in CIDR notation, use 172.16.0.0/16 .  To refer to the single IP address 172.16.0.1 , use 172.16.0.1/32 .

Subnet mask
Subnet bits
Number of IP addresses
255.0.0.0
/8
16,581,375
255.255.0.0
/16
65,025
255.255.255.0
/24
256
255.255.255.128
/25
128
255.255.255.192
/26
64
255.255.255.224
/27
32
255.255.255.240
/28
16
255.255.255.248
/29
8
255.255.255.252
/30
4
255.255.255.254
/31
2
255.255.255.255
/32
1




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