Woozle: Woozle moved page SPF/mechanism/cidr-length to SPF/term/cidr-length

2022-08-18T16:51:31Z

Woozle moved page SPF/mechanism/cidr-length to SPF/term/cidr-length

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Woozle: Created page with "==About== {{fmt/arg|cidr-length}} refers to the CIDR ({{l/wp|Classless Inter-Domain Routing}}) convention for specifying blocks of IP addresses. SPF uses three possible v..."

2022-08-18T15:59:44Z

Created page with "==About== {{fmt/arg|cidr-length}} refers to the CIDR ({{l/wp|Classless Inter-Domain Routing}}) convention for specifying blocks of IP addresses. SPF uses three possible v..."

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==About==
{{fmt/arg|cidr-length}} refers to the [[CIDR]] ({{l/wp|Classless Inter-Domain Routing}}) convention for specifying blocks of IP addresses.

SPF uses three possible versions of this:
* {{fmt/arg|ip4-cidr-length}}: defaults to "/32"
* {{fmt/arg|ip6-cidr-length}}: defaults to "/128"
* {{fmt/arg|dual-cidr-length}}: includes at least one of {{fmt/arg|ip4-cidr-length}} and {{fmt/arg|ip6-cidr-length}}, and possibly both
** If {{fmt/arg|ip6-cidr-length}} appears, it must be prefixed with "/".
** If both appear, {{fmt/arg|ip4-cidr-length}} must be first.

The official and almost-comprehensible RFC documentation has this to say ([https://www.rfc-editor.org/rfc/rfc7208.html#section-5.6 Section 5.6]):
ip4 = "ip4" ":" ip4-network [ ip4-cidr-length ]
ip6 = "ip6" ":" ip6-network [ ip6-cidr-length ]

ip4-cidr-length = "/" ("0" / %x31-39 0*1DIGIT) ; value range 0-32
ip6-cidr-length = "/" ("0" / %x31-39 0*2DIGIT) ; value range 0-128
dual-cidr-length = [ ip4-cidr-length ] [ "/" ip6-cidr-length ]

ip4-network = qnum "." qnum "." qnum "." qnum
qnum = DIGIT ; 0-9
/ %x31-39 DIGIT ; 10-99
/ "1" 2DIGIT ; 100-199
/ "2" %x30-34 DIGIT ; 200-249
/ "25" %x30-35 ; 250-255
; as per conventional dotted-quad notation, e.g., 192.0.2.0

ip6-network = <as per [https://www.rfc-editor.org/rfc/rfc4291#section-2.2 Section 2.2 of {{fmt/brackets|RFC4291}}]>
; e.g., 2001:db8::cd30
<blockquote>
The {{fmt/arg|{{l/same|ip}}}} is compared to the given network. If CIDR prefix length high-order bits match, the mechanism matches.

If ip4-cidr-length is omitted, it is taken to be "/32". If ip6-cidr-length is omitted, it is taken to be "/128". It is not permitted to omit parts of the IP address instead of using CIDR notations. That is, use 192.0.2.0/24 instead of 192.0.2.
</blockquote>

SPF/term/cidr-length - Revision history

Woozle: Woozle moved page SPF/mechanism/cidr-length to SPF/term/cidr-length

Woozle: Created page with "==About== {{fmt/arg|cidr-length}} refers to the CIDR ({{l/wp|Classless Inter-Domain Routing}}) convention for specifying blocks of IP addresses. SPF uses three possible v..."