Non-Octet Boundary Delegation (RFC 4183)
ginermail at gmail.com
Wed Sep 21 19:38:02 UTC 2011
Could anyone tell me if ISC DHCP supports Non-Octet Boundary
Delegation? It supports by ISC BIND as I see but I've not managed to
find the same information related to the DHCP server.
Cut from http://www.ietf.org/rfc/rfc4183.txt
3. Non-Octet Boundary Delegation
In RFC 2317, there is no mechanism for non-octet boundary delegation.
Networks would be represented as being part of the domain of the next
10.100.2.0/26 -> 0-18.104.22.168.in-addr.arpa.
10.20.128.0/23 -> 128-23.20.10.in-addr.arpa.
10.192.0.0/13 -> 192-13.10.in-addr.arpa.
In the event that the entity subnetting does not actually own the
network being subnetted on an octet break, a mechanism needs to be
available to allow for the specification of those subnets. The
mechanism is to allow the use of maskedoctet labels as delegation
For example, consider an entity A that controls a network
10.1.0.0/16. Entity A delegates to entity B the network 10.1.0.0/18.
In order to avoid having to update entries for entity B whenever
entity B updates subnetting, entity A delegates the
0-18.1.10.in-addr.arpa domain (with an NS record in A's DNS tables as
usual) to entity B. Entity B then subnets off 10.1.0.0/25. It would
provide a domain name for this network of
0-25.0.0-18.1.10.in-addr.arpa (in B's DNS tables).
In order to speak about the non-octet boundary case more easily, it
is useful to define a few terms.
Network domain names that do not contain any maskedoctets after the
first (leftmost) label are hereafter referred to as canonical domain
names for that network. 0-22.214.171.124.in-addr.arpa. is the canonical
domain name for the network 10.1.0.0/25.
Network domain names that do contain maskedoctet labels after the
first (leftmost) label can be reduced to a canonical domain name by
dropping all maskedoctet labels after the first (leftmost) label.
They are said to be reducible to the canonical network domain name.
So for example 0-25.0.0-18.1.10.in-addr.arpa. is reducible to
0-126.96.36.199.in-addr.arpa. Note that a network domain name represents
the same network as the canonical domain name to which it can be
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