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ripe-448: Autonomous System (AS) Number Assignment Policies and Procedures ripe-085: Guidelines For The Delegation Of Zones In The 193.in-addr.arpa Domai

Introduction insert:  
insert:  
This document describes the procedures for the delegation of au- insert:  
thority of zones in the 193.in-addr.arpa domain. As of March insert:  
16th 1993 the RIPE NCC has been delegated the authority for the insert:  
193.in-addr.arpa domain from the root. Due to the fact that in insert:  
the 193.x.y address space blocks of 256 class C network numbers insert:  
are further delegated to local registries , the possibility ex- insert:  
ists to also delegate the zone for these blocks in the 193.in- insert:  
addr.arpa domain. This document describes some guidelines and insert:  
procedures for this type of delegation and the delegation of re- insert:  
verse zones for individual class C networks in 193.x.y. insert:  
insert:  
insert:  
A bit more explained insert:  
insert:  
With the assignment of class C network numbers following the CIDR insert:  
(RFC 1338) model, in which large chunks of the address space are insert:  
delegated to one region, and within that region blocks of class C insert:  
network numbers are delegated to service providers and non- insert:  
provider registries, some hierarchy in the address space is insert:  
created, similar to the hierarchy in the domain name space. Due insert:  
to this hierarchy the reverse Domain Name System mapping can also insert:  
be delegated in a similar model as used for the normal Domain insert:  
Name System. For instance, the RIPE NCC has been assigned the insert:  
complete class C address space starting with 193. It is there- insert:  
fore possible to delegate the 193.in-addr.arpa domain completely insert:  
to the RIPE NCC, instead of each and every reverse mapping in the insert:  
193.in-addr.arpa domain to be registered with the INTERNIC. This insert:  
implies that all 193.in-addr.arpa resistrations will be done by insert:  
the RIPE NCC. Even better, since service providers receive com- insert:  
plete class C network blocks from the RIPE NCC, the RIPE NCC can insert:  
delegate the reverse registrations for such complete blocks to insert:  
these local registries. This implies that customers of these insert:  
service providers no longer have to register their reverse domain insert:  
mapping with the root, but the service provider have authority insert:  
over that part of the reverse mapping. This decreases the work- insert:  
load on the INTERNIC and the RIPE NCC, and at the same time in- insert:  
crease the service a provider can offer its customers by improve insert:  
response times for reverse mapping changes . However there are insert:  
some things that need to be examined a bit more closely to avoid insert:  
confusion and inconsistencies. These issues are covered in the insert:  
next section. insert:  
insert:  
insert:  
Procedures for the delegation of direct subdomains of 193.in- insert:  
addr.arpa insert:  
insert:  
1. A secondary nameserver at ns.ripe.net is mandatory for all insert:  
blocks of class C network numbers delegated in the 193.in- insert:  
addr.arpa domain. insert:  
insert:  
2. Because of the increasing importance of correct reverse ad- insert:  
dress mapping, for all delegated blocks a good set of secondaries insert:  
must be defined. There should be at least 2 nameservers for all insert:  
blocks delegated, excluding the RIPE NCC secondary. insert:  
insert:  
3. The delegation of a class C block in the 193.in-addr.arpa insert:  
domain can be requested by sending in a domain object for the insert:  
RIPE database to <[email protected]> with all necessary contact insert:  
and nameserver information. The RIPE NCC will then forward all insert:  
current reverse zones inside this block to the registry, and insert:  
after addition of these by the registry, the NCC will check the insert:  
working of the reverse server. Once everything is setup proper- insert:  
ly, the NCC will delegate the block, and submit the database ob- insert:  
ject for inclusion in the database. An example domain object can insert:  
be found at the end of this document. insert:  
insert:  
4. All reverse servers for blocks must be reachable from the insert:  
whole of the Internet. In short, all servers must meet similar insert:  
connectivity requirements as top-level domain servers. insert:  
insert:  
5. Running the reverse server for class C blocks does not imply insert:  
that one controls that part of the reverse domain, it only im- insert:  
plies that one administers that part of the reverse domain. insert:  
insert:  
6. Before adding individual nets, the administrator of a reverse insert:  
domain must check wether all servers to be added for these nets insert:  
are indeed setup properly. insert:  
insert:  
7. There are some serious implications when a customer of a ser- insert:  
vice provider that uses address space out of the service provider insert:  
class C blocks, moves to another service provider. The previous insert:  
service provider cannot force its ex-customer to change network insert:  
addresses, and will have to continue to provide the appropriate insert:  
delegation records for reverse mapping of these addresses, even insert:  
though it they are no longer belonging to a customer. insert:  
insert:  
8. The registration of the reverse zones for individual class C insert:  
networks will usually be done by the registry administering the insert:  
class C block this network has been assigned from. The registry insert:  
will make the necessary changes to the zone, and update the net- insert:  
work objects in the RIPE database for these networks, to reflect insert:  
the correct "rev-srv" fields. In case the RIPE NCC receives a insert:  
request for the reverse zone of an individual class C network out insert:  
of a block that has been delegated, the request will be forwarded insert:  
to the zone contact for this reverse block. insert:  
insert:  
9. The NCC advises the following timers and counters for direct insert:  
subdomains of 193.in-addr.arpa: 8 hours refresh (28800 seconds), insert:  
2 hours retry (7200 seconds), 7 days expire (604800 seconds) and insert:  
1 day Time To Live (86400 seconds). The retry counter should be insert:  
lowered where connectivity is unstable. insert:  
insert:  
Above procedures are defined to ensure the necessary high availa- insert:  
bility for the 193 reverse domains, and to minimize confusion. insert:  
The NCC will ensure fast repsonse times for addition requests, insert:  
and will in principle update the 193.in-addr.arpa domain at least insert:  
once per working day. insert:  
insert:  
Example domain object to request a block delegation insert:  
insert:  
domain: 202.193.in-addr.arpa insert:  
descr: Pan European Organisations class C block insert:  
admin-c: Daniel Karrenberg insert:  
tech-c: Marten Terpstra insert:  
zone-c: Marten Terpstra insert:  
nserver: ns.eu.net insert:  
nserver: sunic.sunet.se insert:  
nserver: ns.ripe.net insert:  
changed: [email protected] 930319 insert:  
source: RIPE insert:  
insert:  
insert:  
insert:  
Procedures for the delegation of individual network zones by the insert:  
RIPE NCC. insert:  
insert:  
The registration of the reverse zones for individual class C net- insert:  
works will usually be done by the registry administering the insert:  
class C block this network has been assigned from. In case the insert:  
zone corresponding to the class C block has not been delegated, insert:  
the RIPE NCC will automatically add the reverse nameserver as insert:  
specified in the "rev-srv" attribute of the RIPE database object insert:  
for this network, using the following procedures: insert:  
insert:  
1. Because of the increasing importance of correct reverse ad- insert:  
dress mapping, for all delegated networks a good set of secon- insert:  
daries must be defined. There should be at least two nameservers insert:  
for all networks delegated. insert:  
insert:  
2. The "rev-srv" field should ONLY contain one fully qualified insert:  
domain name of a nameserver which is authoritative for the re- insert:  
verse zone for this network. insert:  
insert:  
3. If a network has or is going to have any external connectivi- insert:  
ty, it is strongly recommended that it has at least one reverse insert:  
nameserver that can be reached from all of the Internet. insert:  
insert:  
4. The checking and addition of the reverse zones for single net- insert:  
works is completely automated at the RIPE NCC. Although we do insert:  
our best to check the setup of the nameservers, these does not insert:  
receive the same level of scrutiny as nameservers for blocks of insert:  
class C network numbers. It is the responsibility of the network insert:  
contacts to ensure proper operation. insert:  
insert:  
5. Any problems regarding the reverse zones in 193.in-addr.arpa insert:  
should be directed to <[email protected]>. insert:  
insert:  
The NCC also suggests that similar procedures are set up for the insert:  
delegation of reverse zones for individual class C networks from insert:  
the registries to individual organisations. insert: 