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Skyhigh Security

Configure IP Addresses using CIDR Notation

Use Classless Inter-Domain Routing (CIDR) notation when configuring IP addresses for IP range, IPsec, or GRE authentication and for web policies.

CIDR notation specifies:

  • A routing prefix to a network
  • An IP address or range on the specified network

CIDR syntax consists of an IPv4 or IPv6 address followed by a forward slash and a decimal number. The decimal number specifies the number of bits in the network prefix.

IPv4 network prefixes are allowed to range in size from 8 bits to 32 bits. A 24-bit IPv4 network prefix consists of 256 addresses. IPv6 network prefixes are allowed to range in size from 8 bits to 128 bits. A 120-bit IPv6 network prefix consists of 256 addresses.

Protocol Network prefix (bits) CIDR notation (example) Specified IP address range
IPv4 8-32 127.0.0.0/24 From 127.0.0.0 to 127.0.0.255
IPv6 8-128 2001:db8:1234:0:0:0:0:ff00/120 From 2001:db8:1234:0:0:0:0:ff00
to 2001:db8:1234:0:0:0:0:ffff

 

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