A DNS Database Referral Mechanism

Hi all,

Below is a proposal put together by Wilfried Woeber and myself to 
address the need for a referral mechanism for domain name queries in
the RIPE database. 

The mechanism is designed to address the immediate needs of those
trying to get domain related information, and of DNS administrators
trying to provide it. Certainly the mechanism may be adapted with time
(see the three options below), however we choose to start with
something that can provide the required functionality immediately.

We hope to discuss this proposal on the mailing lists and in the 
database and dns working group meetings in Dublin.

Carol Orange
RIPE NCC


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RIPE Database Referral Mechanism for Domain Queries - A Proposal

Carol Orange & Wilfried Woeber, April 1997
------------------------------------------
In the following, we propose a mechanism for forwarding whois queries
to the appropriate database if the RIPE database does not contain the
authoritative data for a given tree in the DNS name space or subset 
thereof. It is thus applicable for the "domain" object only:

domain:      [mandatory]  [single]    
descr:       [mandatory]  [multiple]  
admin-c:     [mandatory]  [multiple]  
tech-c:      [mandatory]  [multiple]  
zone-c:      [mandatory]  [multiple]  
nserver:     [optional]   [multiple]  
sub-dom:     [optional]   [multiple]  
dom-net:     [optional]   [multiple]  
remarks:     [optional]   [multiple]  
notify:      [optional]   [multiple]  
mnt-by:      [optional]   [multiple]  
mnt-lower:   [optional]   [multiple]  
changed:     [mandatory]  [multiple]  
source:      [mandatory]  [single]    

The goal of the mechanism is to provide a means for TLD domain 
administrators (and other "high-level" domains) to enable users to 
obtain an authoritative response for a domain object query sent to 
the RIPE database, regardless of whether the data for the domain is 
maintained in the RIPE database itself.

Algorithm
---------
If the following query is submitted to the RIPE database:

	whois [flags] xxx.yyy.zz

the algorithm will work as follows:

-------
NAME="xxx.yyy.zz"

until (NAME = "") {
	If object with domain = NAME found,
		If object contains referral (see "Referral" below)
			forward query (see "Forward" below)
		Else
			return object
	Else
		Strip(NAME) (xxx.yyy.zz -> yyy.zz, etc)
}


NOTES
-----
1. We move up the tree here, and return the next level answer
if present. If the query requests "tuintje.cwi.nl" (Piet, do you
mind?), they currently get "No entries found ...". In the new
mechanism, they would get:

domain:      cwi.nl
.
.
.
mnt-by:      NL-DOMREG
changed:     hostmaster at domain-registry.nl 19950227
source:      RIPE

Moreover, if the object for cwi.nl contains a referral, the query 
would be passed on to the specified server as explained below.

2. The algorithm will be set off by any query which causes a search in
the domain object index. This means any query with "-T domain", or
any general query (no -T flag) with something that "looks like a
domain".

Referral
--------
A whois referral can be entered in a "refer" attribute by specifying 
the type of database in which the data is maintained, and the domain
name of the server that should be queried:

refer: <type> <host> <port>

where
    <type> is one of RIPE, InterNIC or SIMPLE, indicating which
           style of whois service is provided.

    <host> is the DNS name of the whois service.

    <port> is the TCP port number (optional: 43 is the default).


Examples:

(CWI again):
refer: RIPE domain-registry.nl 43

(InterNIC):
refer: InterNIC whois.internic.net

(Generic):
refer: SIMPLE my.dns.tld

Initially queries for the three types of databases shown here 
would be supported. If RIPE is specified, then the initial query
together with all arguments would be passed to the specified whois
server. If an InterNIC database is specified, then a query 
expected by the InterNIC database software would be generated for the
specified domain name. The same would be true of "SIMPLE". In that case
a simple query for the domain name would be passed on. 

If in the future, another domain name database is implemented with a
given query language, it can be added.

Forward
-------
If the TLD object contains a whois referral, we can 

a) query the server, and pass the response to the requester, preceded
by a comment of the form: "The following data has been obtained from 
domain-registry.nl".
b) pass the referral to the requester
c) send the query to the server with the address of the requester

a) has the advantage of giving the user an immediate answer, and 
requires that only the RIPE database software be modified, not that of
the TLD admins. Nothing has to be changed there. 

a) has the disadvantage that the RIPE server can become a bottleneck. 
However, local mirrors of referred to databases can be set up on a
RIPE NCC server to alleviate this problem. 

Summary
-------
We propose the above mechanism with (option (a) request forwarding)
be used for TLD/domain referrals.  We believe it will make the domain 
part of the database more transparent to users and easier to manage 
for TLD administrators. 


Acknowledgements
----------------
We would like to thank Chris Fletcher, Daniel Karrenberg, and David
Kessens for useful comments.