193.in-addr.arpa block delegation procedures (draft)

Folks,

It seems that the delegation of the 193.in-addr.arpa domain will take place
during the root zone update of today. In order to be able to delegate class C
blocks in this zone, we have drafted some procedures for this.

Please read the paper below and comment within one week. We will finalize
this paper next week, and then start delegating blocks of Cs in the domain.

Cheers,

-Marten



			Guidelines for the delegation
			  of class C blocks in the
			   193.in-addr.arpa domain

			       Marten Terpstra

				 March 1993

				    1.0


Introduction

This document describes the procedures for the delegation of authority
of zones in the 193.in-addr.arpa domain. As of March 16th 1993 the
RIPE NCC has been delegated the authority for the 193.in-addr.arpa
domain from the root. Due to the fact that in the 193.x.y address space
blocks of 256 class C network numbers are further delegated to local
registries and national registries, the possibility exists to also
delegate the zone for these blocks in the 193.in-addr.arpa domain.
This document describes some guidelines and procedures for
this type of delegation.


A bit more explained

With the assignment of class C network numbers following the CIDR (RFC
1338) model, in which large chunks of the address space are delegated to
one region, and within that region blocks of class C network numbers are
delegated to service providers and national registries, some hierarchy
in the address space is created, similar to the hierarchy in the domain
name space. Due to this hierarchy the reverse Domain Name System mapping can
also be delegated in a similar model as used for the normal Domain Name
System. For instance, the RIPE NCC has been delegated the complete class
C address space starting with 193. It is therefore possible to delegate
the 193.in-addr.arpa domain completely to the RIPE NCC, in stead of each
and every reverse mapping in the 193.in-addr.arpa domain to be
registered with the INTERNIC. This implies that all 193.in-addr.arpa
resistrations will be done by the RIPE NCC. Even better, since service
providers receive complete class C network blocks from the RIPE NCC, the
RIPE NCC can delegate the reverse registrations for such complete blocks
to these local registries. This implies that customers of these service
providers no longer have to register their reverse domain mapping with
the root, but the service provider have authority over that part of the
reverse mapping. This decreases the workload on the INTERNIC and the
RIPE NCC, and at the same time increase the service a provider can offer
its customers and response times for such additions. However there are
some things that need to be examined a bit more closely to avoid
confusion and inconsistencies. These issues are covered in the next
section.

Procedures

1. A secondary nameserver at ns.ripe.net is mandatory for all blocks of
class C network numbers delegated in the 193.in-addr.arpa domain.

2. Because of the increasing importance of correct reverse address
mapping, for all delegated blocks a good set of secondaries must be
defined. There should be at least 2 nameservers for all blocks
delegated, excluding the RIPE NCC secondary.

3. All reverse servers for blocks must be reachable from the whole of
the Internet. In short, all servers must meet similar connectivity
requirements as top-level domain servers.

4. Running the reverse server for class C blocks does not imply that one
controls that part of the reverse domain, it only implies that one
administers that part of the reverse domain.

5. Before adding individual nets, the administrator of a reverse domain
must check wether all servers to be added for these nets are indeed
setup properly.

6. There are some serious implications when a customer of a service
provider that uses address space out of the service provider class C
blocks, moves to another service provider. The service provider cannot
force its ex-customer to change network addresses, and will have to
continue to provide the appropriate delegation records for reverse
mapping of these addresses, even though it is no longer a customer of
his.

Above procedures are defined to ensure the necessary high availability for
the 193 reverse domains, and to minimize confusion. The NCC will ensure fast
repsonse times for addition requests, and will in principle update the
193.in-addr.arpa domain at least once per working day.

The NCC also suggests that similar procedures are set up for the delegation
of reverse zones from the registries to individual organisations.