Internet Engineering Task Force C. Martinez, Ed.
Internet-Draft LACNIC
Intended status: Informational L. Zhou, Ed.
Expires: August 18, 2014 CNNIC
G. Rada
LACNIC
February 14, 2014
Redirection Service for Registration Data Access Protocol
draft-ietf-weirds-redirects-03
Abstract
The traditional WHOIS protocol has several important shortcomings,
and over the past few years several approaches to a better
Registration Data Access Protocol (RDAP) have been discussed and
proposed.
It is worth noting that the term WHOIS is sometimes used
interchangeably to mean either (a) the registration data itself or
(b) the protocol used to access registration data
Among these shortcomings, different registries operate different
WHOIS services. For users this means that several WHOIS queries to
different registries may be necessary in order to obtain data for a
given resource.
This document describes a redirection service for RDAP queries. This
service allows clients to query a single RDAP service and expect
either an authoritative answer or a redirection hint pointing to
another, possibly authoritative, RDAP server.
The solution implemented proposed here applies to Regional Internet
Registries(RIRs) and Domain Name Registries(DNRs).
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 18, 2014.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4
2. Proposed Approach . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. The REST Approach to Web Services . . . . . . . . . . . . . 4
2.2. Query Redirection for RDAP Queries . . . . . . . . . . . . 4
2.3. A Joint RDAP Tree through HTTP Redirection . . . . . . . . 5
2.4. The Redirection Table. The Bootstrap Problem. . . . . . . . 7
2.5. Loops in Redirection . . . . . . . . . . . . . . . . . . . 8
2.6. Service Discovery . . . . . . . . . . . . . . . . . . . . . 8
2.7. Security Considerations . . . . . . . . . . . . . . . . . . 8
3. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Normative References . . . . . . . . . . . . . . . . . . . 8
3.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
A user interested in obtaining registration information for a given
number or domain resource normally uses the WHOIS service provided by
the RIRs and DNRs.
In order to avoid having to query several databases until obtaining
an answer, some approaches have been discussed and implemented in the
past, most notably the Joint WHOIS [lacnic-joint-whois] initiative.
However, among other shortcomings, Joint WHOIS is implemented using
proxies and server-side referrals.
The RDAP protocol (draft-ietf-weirds-using-http [I-D.ietf-weirds-
using-http]) makes it comparatively easy to implement client-side
redirects based on normal HTTP 1.1 semantics and behavior.
The goal of this I-D is to describe an implementation of an RDAP
redirection service and to encourage discussion on the topic of
redirects in this problem domain.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Proposed Approach
2.1. The REST Approach to Web Services
While a full introduction to REST and RESTful interfaces is out of
the scope of this document it is important to note that these
interfaces employ the verbs defined in HTTP (GET, POST, HEAD, DELETE)
and HTTP response codes to signal the semantics and outcomes of an
operation.
As WHOIS is a read-only service only the GET and HEAD verbs are
usually implemented.
HTTP status codes provide signaling for errors and other conditions,
including the concept of "client-side redirection" as outlined below.
2.2. Query Redirection for RDAP Queries
Each RDAP server should answer directly only those queries for which
it is authoritative. In this case, being authoritative equals
"having direct access to a given registry database".
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For all other queries, a RDAP server could provide a 301 MOVED
PERMANENTLY redirect answer pointing to an URL hosted on a different
RDAP server.
As all requests are to be performed employing HTTP GETs, a user agent
can transparently follow the HTTP 30x redirection hints ([RFC2616])
until obtaining a non-error answer (HTTP 20x) or an unrecoverable
error condition (HTTP 40x or 50x).
2.3. A Joint RDAP Tree through HTTP Redirection
When a registry does not have the authoritative answers to the user
agent's query, user agent's query can be redirected to a redirection-
only RDAP server which could provide the authoritative RDAP server
address.
The redirect server is responsible for tracking and returning the
authoritative sources for IP, AS, domain name, name server or entity
queries. All the query format are described in the
draft-ietf-weirds-rdap-query [I-D.ietf-weirds-rdap-query]. We will
call this redirect server "the redirector".
The redirect server needs access to data sources that, given a
queried resource, provide a pointer to the authoritative RDAP server.
For lack of a better name, we will call this data source the
"redirection table".
Assuming the redirector has access to a redirection table, the
following pseudo code describes its expected behaviour:
while(true) {
query = read_query_from_network()
auth_rdap_svr = redirect_table_lookup (query.resource)
if (auth_rdap_svr != null) {
write_http_301(auth_rdap_svr)
} else {
write_http_404("resource not in redirect table")
}
}
Redirector state machine
Figure 1
Figure 2 shows the general scheme of a single RDAP Redirection
Service serving three different RIRs standalone RDAPs while providing
a seamless query interface to clients.
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......................
| |
| RDAP REDIRECTOR |
| |
`....................'
_, | ._
,,' | `.
,-' | `-.
,-' | `._
_,-' | `.
.' | `-.
+-----------Y +-------------. ,------------b
| LACNIC | | RIPE-NCC | | ARIN |
| | | | | |
'`''''''''''' '`'''''''''''' '`''''''''''''
RDAP Joint WHOIS Tree.
Figure 2
Figure 3 shows how HTTP 301 redirection hints guide a client looking
for registration data for the IPv4 address 23.1.1.1 (administered by
ARIN) from LACNIC's WHOIS, the redirector and finally ARIN's WHOIS.
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LACNIC REDIRECTOR ARIN
RDAP RDAP RDAP
. . .
Q: 23.1.1.1? ----> | | |
| | |
<-- HTTP 301 --- | | |
('Try Redirector') | | |
| | |
| | |
Q: 23.1.1.1? -----------------> | |
| |
<---------- HTTP 301 --------| |
('Try ARIN RDAP') | |
| |
|
Q: 23.1.1.1? -------------------------------> |
|
<---------- HTTP 200 --------------------- |
(WHOIS response is returned) |
|
|
.
Querying WHOIS data for 23.1.1.1
Figure 3
2.4. The Redirection Table. The Bootstrap Problem.
For the redirection table lookup function, the redirector can either
have pre-populated local table or have access to a service provided
by some form of directory service. How either this local table or
directory service is fed is known as the "bootstrapping problem".
The bootstrapping problem was initially declared out of scope of the
WEIRDS WG. However, the problem has been discussed and several
proposals have been presented (**insert references to Marc's docs**).
Some of these solutions contemplate using the DNS tree as directory
service while others, for the specific case of number resources,
contemplate using IANA's XML registry files as seed files for a local
redirection table.
The bootstrapping problem needs to be addressed differently for names
and numbers as the coount of potential authoritative RDAP servers for
names (huge) is vastly different from the count for numbers
(currently 5).
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2.5. Loops in Redirection
When redirection is used there is always the risk that bogus user-
agents and applications or malicious user can create loops that in
turn may become Denial of Service attacks.
Commonly used user agents (including HTTP libraries) have loop
detection features that are deemed sufficient for breaking loops in
RDAP.
2.6. Service Discovery
TBD
2.7. Security Considerations
HTTP 30x-based redirection could offer an attack vector for a Man-in-
the-Middle type of attack, where the adversary modifies the
redirection URL offered by the server to the client.
For example, an attacker able to modify HTTP traffic could modify the
redirect URL from
http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1 and
change it into
http://www.labs.somenic.net/restwhois/rwhois_redir/ip/23.1.1.1, where
bogus information can be offered to the client.
This particular type of attack can be prevented by usint HTTPS for
the RDAP connection. However, this certainly places a load burden
upon the servers.
While security practices are outside the scope of this document, the
authors believe it is important to identify such problematic use
cases to any DNR or RIR that may implement the redirection WHOIS
service.
3. References
3.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
3.2. Informative References
[I-D.ietf-weirds-rdap-query]
Newton, A. and S. Hollenbeck, "Registration Data Access
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Protocol Query Format", draft-ietf-weirds-rdap-query-02
(work in progress), December 2012.
[I-D.ietf-weirds-using-http]
Newton, A., Ellacott, B., and N. Kong, "Using the
Registration Data Access Protocol (RDAP) with HTTP",
draft-ietf-weirds-using-http-01 (work in progress),
December 2012.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[lacnic-joint-whois]
LACNIC, "Joint WHOIS", 2005, <ftp://
anonymous@ftp.registro.br/pub/gter/gter20/
02-jwhois-lacnic.pdf>.
Authors' Addresses
Carlos M. Martinez (editor)
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: carlos@lacnic.net
Linlin Zhou (editor)
CNNIC
No. 4, South 4th Steet, Zhongguancun
Beijing, 100190
China
Phone: +8610-5881-2677
Email: zhoulinlin@cnnic.cn
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Gerardo Rada
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: gerardo@lacnic.net
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