11.4. IP Address Restriction

SavaPage uses CIDR Notation for IP address restriction where needed.

11.4.1. CIDR Notation

Classless Inter-Domain Routing (CIDR) is developed in the 1990s as a standard scheme for routing network traffic across the Internet.

CIDR notation is a syntax for specifying IP addresses and their associated prefix size, the latter being equivalent to the number of leading 1 bits in the routing prefix mask. The notation starts with an IP address expressed according to the standards of IPv4 or IPv6[25]. It is followed by a separator character, the slash (/) character, and the prefix size expressed as a decimal number.

Some examples:

  • represents the given IPv4 address and its associated routing prefix, or equivalently, its subnet mask This represents the host address range -

  • CIDR represents the single IPv4 address

  • CIDR 2021:661:4cc6:1:5561:96ff:ca11:d4a/128 represents the single IPv6 address 2021:661:4cc6:1:5561:96ff:ca11:d4a.

  • CIDR 2021:661:4cc6:1:5561:96ff:ca11:d00/120 represents a block size of 256 with First IP 2021:661:4cc6:1:5561:96ff:ca11:d00 and a Last IP 2021:661:4cc6:1:5561:96ff:ca11:dff .

11.4.2. CIDR Set

For SavaPage use only we define a CIDR Set as a concatenation of single CIDR notations separated by any of the characters space, comma or semicolon.

[25] CIDR notation for IPv6 is described in RFC 4291.