CIDR Format

To configure a block of allowable IP addresses, use the CIDR format. CIDR specifies an IP address range by the combination of an IP address and its associated network mask. CIDR notation uses the following format:


192.30.250.00/18
  • The 192.30.250.00 in this example is the network address itself. The 18 indicates that the first 18 bits are the network part of the address, leaving the last 14 bits for specific host addresses.

The following table contains more examples:

CIDR Format
Equivalent Netmask
10.10.0.0/16
255.255.0.0
10.10.10.0/24
255.255.255.0
10.10.10.0/28
255.255.255.240