Internet Engineering Task Force C. Martinez, Ed.
Internet-Draft A. Servin, Ed.
Intended status: Informational LACNIC
Expires: August 5, 2013 L. Zhou, Ed.
CNNIC
D. Gomez
G. Rada
LACNIC
Feb 2013
Redirection Service for Registration Data Access Protocol
draft-ietf-weirds-redirects-01
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.
Among these shortcomings, different registries operate different
WHOIS services. For users this implies 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 RESTful WHOIS
queries. This service allows users to query a single WHOIS service
and be redirected to the authoritative registry.
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
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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
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on August 5, 2013.
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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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 RESTful WHOIS Queries . . . . . . . 4
2.3. A Single RESTful WHOIS trough HTTP Redirection . . . . . . 5
2.4. Loops in Redirection . . . . . . . . . . . . . . . . . . . 6
3. Service Discovery . . . . . . . . . . . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Normative References . . . . . . . . . . . . . . . . . . . 10
5.2. Informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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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 RESTful approach to WHOIS services (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 a RESTful WHOIS 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 <http://www.rest.org>
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 verb is 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 RESTful WHOIS Queries
Each RESTful WHOIS 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 RESTful WHOIS server could provide a 301
MOVED PERMANENTLY redirect answer pointing to an URL hosted on a
different RESTful WHOIS 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 Single RESTful WHOIS trough HTTP Redirection
When a registry does not have the authoritative answers to the user
agent's query, user agent's query will be redirected to a
redirection-only RESTful WHOIS server which could provide the
authoritative WHOIS 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] Until now,
there are some alternative solutions for the bootstrapping problem of
redirect server, such as using DNS SRV or NAPTR records. But this
problem is out of scope of this document and will be discussed
further in the following drafts in WEIRDS working group.
Figure 1 shows the general scheme of a single RESTWhois Redirection
Service serving three different RIRs standalone RESTWhois while
providing a seamless query interface to clients.
......................
| |
| WHOIS REDIRECTOR |
| |
`....................'
_, | ._
,,' | `.
,-' | `-.
,-' | `._
_,-' | `.
.' | `-.
+-----------Y +-------------. ,------------b
| LACNIC | | RIPE-NCC | | ARIN |
| | | | | |
'`''''''''''' '`'''''''''''' '`''''''''''''
RESTful Joint WHOIS Tree.
Figure 1
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Figure 2 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.
LACNIC REDIRECTOR ARIN
WHOIS WHOIS WHOIS
. . .
Q: 23.1.1.1? ----> | | |
| | |
<-- HTTP 301 --- | | |
('Try Redirector') | | |
| | |
| | |
Q: 23.1.1.1? -----------------> | |
| |
<---------- HTTP 301 --------| |
('Try ARIN WHOIS') | |
| |
|
Q: 23.1.1.1? -------------------------------> |
|
<---------- HTTP 200 --------------------- |
(WHOIS response is returned) |
|
|
.
Querying WHOIS data for 23.1.1.1
Figure 2
2.4. 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.
To minimize the risk of loops created by bogus applications and user-
agents operators MAY use the mechanism shown in Section 3.1.
However, this mechanism could be forged and bypassed by malicious
users possibly creating a Denial of Service attack against the
operator. To avoid completely the risk of DoS operators should use
other methods such as rate-limit and authentication that are outside
the scope of this document.
One of the challenges by using redirection is loop avoidance. Even
though recommendation from REFERENCE** indicates that user-agents
should have a mechanism to break loops, due to sometimes not
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carefully coded user-agents and other applications or due to
malicious users' activities loops that could end up in a Denial of
Service for the RESTful WHOIS operator.
A simple scenario that creates a loop is shown in Figure 3. A user
request (1) an object from Operator 1; Operator 1 do not have the
object but it has a pointer that Operator 2 has it, so it redirects
(2) the user to Operator 2; user request Object X to Operator 2 (3);
Operator 2 does not have the object either object but it has a
pointer that Operator 1 has it, so it redirects (4) the user to
Operator 1; it creates a loop (5).
+--------------+ +--------------+
| | | |
| Operator A | | Operator B |
| | | |
+---^-----+----+ +----^----.----+
1) | | 2) 3) | | 4) Redirect
Request | | Redirect Request | | to
Object X | | to Object X | | Operator A
| | Operator B | |
| |____________ _______________| |
|_______________ | | _________________|
| | | |
+--------------+
| | 5) Loop
| User |
| |
+--------------+
A simple loop
Figure 3
The loop described could be avoided by simple forbidding redirecting
a response when the query has been originated by a redirect. However
this solution only allows one redirection. A less restrictive
approach forbidding redirection to only when the destination is the
same than the originator for the redirection does not work either as
shown in Figure 4.
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+--------------+ +--------------+
| | | |
| Operator A | | Operator B |
| | | |
+---^-----+----+ +----^----+----+
1) | | 2) 3) | | 4)Redirect
Request | | Redirect Request | | to
Object X | | to Object X | | Operator C
| | Operator B | |
| |____________ _____________| |
|_______________ | | _______________|
| | | |
+---\/------\/-+
7) Loop | |
| User |
| |
+---^-----+----+
6) Redirect | | 5)
to Operator A | | Request
| | Object X
+--------\/----+
| |
| Operator C |
| |
+--------------+
A more complex loop.
Figure 4
In the scenario depicted in Figure 4 the user request object X from
Operator A which redirects him/her to Operator B which in turn
redirects the user to Operator C. Operator C then redirects the user
back to Operator A again creating a loop.
To avoid loops created by not well-programmed user-agents or
applications when redirecting operators MAY append or modify a
special URI indicating that a redirection and how many times it has
been done. The format of the URI is described as follows.
When a RESTful WHOIS operator redirects a user to retrieve an object
from another operator, the operator making the redirection operator
MAY append or modify a special URI.
When using an URI to indicate redirection, the URI MUST have the
following structure:
/redirect/[step]
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Where [step] is a consecutive counter that MUST be increased by every
operator when the URI is encountered in a query object.
When an operator is redirecting a query for the first time it MAY
append the redirection URI to the original URL. If the redirection
URI is used, it MUST use the format previously described and it MUST
set "step" equal to 1. For example, the URL
"http://whois.lacnic.net/restfulwhois/ip/200.7.84.0/24" would be
replaced by
"http://whois.example.com/restfulwhois/ip/200.7.84.0/24/redirect/1"
If an operator receives a request with the redirect URI it first
SHOULD check if "step" is shorter that the defined threshold. If it
does the operator SHOULD strip it and process the query. If the
query requires further redirection the operator MAY use the
redirection URI and it MUST increase "step" in one.
Operators that support the redirect URI MUST never create a new
redirect that contain a step value greater that their locally set
threshold. However if the operator has an authoritative response to
the agent it MUST respond regardless to the threshold value.
3. Service Discovery
TBD
4. Security Considerations
Firstly, redirect server settings cannot be modified by someone other
than the user validated by the redirection server.
Secondly, insure the redirection URL data must not be able to modify
URL in data transmission process. Such as
http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1 cannot
be modified to
http://www.labs.somenic.net/restwhois/rwhois_redir/ip/23.1.1.1.
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.
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5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
5.2. Informative References
[I-D.ietf-weirds-rdap-query]
Newton, A. and S. Hollenbeck, "Registration Data Access
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
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Arturo L. Servin (editor)
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: aservin@lacnic.net
Linlin Zhou (editor)
CNNIC
No. 4, South 4th Steet, Zhongguancun
Beijing, 100190
China
Phone: +8610-5881-2677
Email: zhoulinlin@cnnic.cn
Dario Gomez
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: dario@lacnic.net
Gerardo Rada
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: gerardo@lacnic.net
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