INTERNET-DRAFT Eric A. Hall
Document: draft-ietf-crisp-lw-asn-00.txt July 2002
Expires: January, 2003
Category: Experimental
Defining and Locating Autonomous System Numbers
using the Internet Resource Query Service
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026.
Internet-Drafts are working documents of the Internet Engineering
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1. Abstract
This document defines LDAP schema and searching rules for
autonomous system numbers, in support of the Internet Resource
Query Service described in [ldap-whois].
Internet Draft draft-ietf-crisp-lw-asn-00.txt July 2002
2. Definitions and Terminology
This document unites, enhances and clarifies several pre-existing
technologies. Readers are expected to be familiar with the
following specifications:
RFC 2247 - Using Domains in LDAP/X.500 DNs
RFC 2251 - Lightweight Directory Access Protocol (v3)
RFC 2252 - Lightweight Directory Access Protocol (v3):
Attribute Syntax Definitions.
RFC 2254 - The String Representation of LDAP Search Filters
[ir-dir-req] - <draft-newton-ir-dir-requirements-00.txt> -
Internet Registry Directory Requirements
[ldap-whois] - <draft-ietf-crisp-lw-core-00.txt> - The
Internet Resource Query Service and the Internet Resource
Schema
The following abbreviations are used throughout this document:
DIT (Directory Information Tree) - A DIT is a contained
branch of the LDAP namespace, having a root of a particular
distinguished name. "dc=example,dc=com" is used throughout
this document as one DIT, with many example entries being
stored in this DIT.
DN (Distinguished Name) - A distinguished name provides a
unique identifier for an entry, through the use of a multi-
level naming syntax. Entries are named according to their
location relevant to the root of their containing DIT. For
example, "cn=inetResources,dc=example,dc=com" is a DN which
uniquely identifies the "inetResources" entry within the
"dc=example,dc=com" DIT.
RDN (Relative DN) - An RDN provides a locally-scoped unique
identifier for an entry. A complete, globally-unique DN is
formed by concatenating the RDNs of an entry together. For
example, "cn=admins,cn=inetResources,dc=example,dc=com"
consists of two RDNs ("cn=admins" and "cn=inetResources")
within the "dc=example,dc=com" DIT. RDNs are typically only
referenced within their local scope.
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OID (Object Identifier) - An OID is a globally-unique,
concatenated set of integers which provide a kind of
"serial number" to attributes, object classes, syntaxes and
other schema elements.
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.
3. The inetAsNumber Object Class
The inetAsNumber object class is a structural object class which
provides administrative information about a specific autonomous
system (AS) number. AS numbers are used to identify routing
domains, allowing multiple discontiguous IPv4 and IPv6 network
blocks to be referenced with a single, globally-unique identifier.
3.1. Naming syntax
The naming syntax for AS number entries MUST follow the form of
"cn=<inetAsNumberSyntax>,cn=inetResources,<dc-DIT>". Each AS
number which is managed as a discrete LDAP-WHOIS network resource
MUST have a dedicated entry in each of the DITs which provide
public LDAP-WHOIS data regarding that autonomous system.
The inetAsNumberSyntax component of an entry is subject to DN
rules, although the inetAsNumberSyntax is also used for search and
compare operations, and is therefore subject to specific syntax
rules. The AS number syntax uses the decimal equivalent of a 16-
bit autonomous system number, with the non-affective leading
zeroes removed. An augmented BNF for this syntax is as follows:
inetAsNumberSyntax = decimal value between "0" and "65535"
inclusive, with the non-affective leading zeroes removed
For example, an entry for AS number "1" from the "dc=arin,dc=net"
DIT would have a DN of "cn=1,cn=inetResources,dc=arin,dc=net",
while an entry for AS number "65535" from the same DIT would have
a DN of "cn=65535,cn=inetResources,dc=arin,dc=net".
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3.2. Schema definition
AS number entries MUST exist with the top, inetResources and
inetAsNumber object classes defined. If an entry exists as a
referral, the entry MUST also be defined with the referral object
class, in addition to the above requirements.
The inetAsNumber object class is a structural object class which
is subordinate to the inetResources object class, and which MUST
be treated as a container class capable of holding additional
subordinate entries. The inetAsNumber object class has no
mandatory attributes, although it does have several optional
attributes.
The inetAsNumber object class defines attributes which are
specific to autonomous systems and their associated routing
domains, such as the delegation date, and the status of the
delegation. The inetAsNumber object class is subordinate to the
inetResources object class, so it inherits those attributes as
well.
Some of the inetAsNumber object class attributes define contact-
related referrals which provide LDAP URLs that refer to
inetOrgPerson entries, and these entries will need to be queried
separately if detailed information about a particular contact is
required. The contact attribute values follow the same rules as
the labeledURI attribute defined in RFC 2079, with additional
restrictions described in [ldap-whois].
The various ModifiedBy and ModifiedDate attributes SHOULD be
treated as operational attributes. Their values SHOULD be filled
in automatically by the database management application, and
SHOULD NOT be returned except when explicitly requested.
The network-specific attributes MUST only contain network
addresses which are directly associated with the AS number, and
MUST use the largest superior prefix delegated to those networks
(using the inetIpv4NetworkSyntax and inetIpv6NetworkSyntax rules);
these attributes MUST NOT contain host or subnet addresses which
are subordinate to another value which is already listed, and
these attributes MUST NOT contain network addresses of networks
which are associated with any other AS number.
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The schema definition for the inetAsNumber object class is as
follows:
inetAsNumber
( 1.3.6.1.4.1.7161.1.4.0 NAME 'inetAsNumber' DESC 'Autonomous
system attributes.' SUP inetResources STRUCTURAL MAY (
inetAsnDelegationStatus $ inetAsnDelegationDate $
inetAsnDelegationModifiedDate $
inetAsnDelegationModifiedBy $ inetAsnContacts $
inetAsnContactsModifiedBy $ inetAsnContactsModifiedDate $
inetAsnRoutingContacts $ inetAsnRoutingContactsModifiedBy
$ inetAsnRoutingContactsModifiedDate ) )
The attributes from the inetIpv4Network object class are described
below:
inetAsnContacts
( 1.3.6.1.4.1.7161.1.4.2 NAME 'inetAsnContacts' DESC
'Contacts for reporting problems with this routing
domain.' EQUALITY caseExactMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.15 )
inetAsnContactsModifiedBy
( 1.3.6.1.4.1.7161.1.4.3 NAME 'inetAsnContactsModifiedBy'
DESC 'Person who last modified the inetAsnContacts
attribute.' EQUALITY distinguishedNameMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE USAGE
distributedOperation )
inetAsnContactsModifiedDate
( 1.3.6.1.4.1.7161.1.4.4 NAME 'inetAsnContactsModifiedDate'
DESC 'Last modification date of the inetAsnContacts
attribute.' EQUALITY generalizedTimeMatch ORDERING
generalizedTimeOrderingMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.24 SINGLE-VALUE USAGE
distributedOperation )
inetAsnDelegationDate
( 1.3.6.1.4.1.7161.1.4.5 NAME 'inetAsnDelegationDate' DESC
'Date of original delegation.' EQUALITY
generalizedTimeMatch ORDERING generalizedTimeOrderingMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 SINGLE-VALUE )
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inetAsnDelegationModifiedBy
( 1.3.6.1.4.1.7161.1.4.6 NAME 'inetAsnDelegationModifiedBy'
DESC 'Person who last modified the inetAsnDelegationStatus
attribute.' EQUALITY distinguishedNameMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE USAGE
distributedOperation )
inetAsnDelegationModifiedDate
( 1.3.6.1.4.1.7161.1.4.7 NAME 'inetAsnDelegationModifiedDate'
DESC 'Last modification date of the
inetAsnDelegationStatus attribute.' EQUALITY
generalizedTimeMatch ORDERING generalizedTimeOrderingMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 SINGLE-VALUE USAGE
distributedOperation )
inetAsnDelegationStatus
( 1.3.6.1.4.1.7161.1.4.8 NAME 'inetAsnDelegationStatus' DESC
'Current delegation status code for this AS number.'
EQUALITY numericStringMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.27{2} SINGLE-VALUE )
NOTE: In an effort to facilitate internationalization and
programmatic processing, the current status of a delegation
is identified by a 16-bit integer. The values and status
mapping is as follows:
0 Reserved delegation (permanently inactive)
1 Assigned and active (normal state)
2 Assigned but not yet active (new delegation)
3 Assigned but on hold (disputed)
4 Assignment revoked (database purge pending)
Additional values for the inetIpv6DelegationStatus
attribute are reserved for future use, and are to be
administered by IANA. Note that there is no status code for
"unassigned"; unassigned entries SHOULD NOT exist, and
SHOULD NOT be returned as answers.
inetAsnRoutingContacts
( 1.3.6.1.4.1.7161.1.4.9 NAME 'inetAsnRoutingContacts' DESC
'Contacts for routing issues with this IPv4 network.'
EQUALITY caseExactMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.15 )
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inetAsnRoutingContactsModifiedBy
( 1.3.6.1.4.1.7161.1.4.10 NAME
'inetAsnRoutingContactsModifiedBy' DESC 'Person who last
modified the inetAsnRoutingContacts attribute.' EQUALITY
distinguishedNameMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE USAGE
distributedOperation )
inetAsnRoutingContactsModifiedDate
( 1.3.6.1.4.1.7161.1.4.11 NAME
'inetAsnRoutingContactsModifiedDate' DESC 'Last
modification date of the inetAsnRoutingContacts
attribute.' EQUALITY generalizedTimeMatch ORDERING
generalizedTimeOrderingMatch SYNTAX
1.3.6.1.4.1.1466.115.121.1.24 SINGLE-VALUE USAGE
distributedOperation )
The inetAsNumberSyntax syntax is as follows:
inetAsNumberSyntax
( 1.3.6.1.4.1.7161.1.4.1 NAME 'inetAsNumberSyntax' DESC 'An
autonomous system number.' )
3.3. Example
An example of the inetAsNumber object class is shown in Figure 1
below, with attributes from the inetResources object class also
being used to provide administrative contacts. This data is a
result of a query which was sent to the LDAP servers associated
with the "arin.net" domain.
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cn=65535,cn=inetResources,dc=arin,dc=net
[top object class]
[inetResources object class]
[inetAsNumber object class]
|
+-attribute: description
| value: "The example.net network"
|
+-attribute: inetAsnContacts
| value: "ldap://ldap.example.com/cn=hostmaster,ou=admins,
| dc=example,dc=net"
|
+-attribute: inetGeneralContacts
value: "ldap://ldap.example.com/cn=admins,ou=admins,
dc=example,dc=net"
Figure 1: The inetAsNumber delegation entry for AS 65535.
4. inetAsNumber equalityMatch
The inetAsNumber object class can be searched using relatively
simple equalityMatch filters.
In order to ensure that all of the relevant entries (including any
referrals) are found, the search filters for these resources MUST
specify two distinct elements: the object class of the resource
being queried, and the naming element of the resource specified as
a distinguished name attribute.
For example, a query for "(&(objectclass=inetAsNumber)(cn:dn:1))"
with a search base of "cn=inetResources,dc=example,dc=com" would
find all of the inetAsNumber object class entries associated with
AS number "1" in the LDAP-WHOIS branch of "dc=example,dc=com".
Response entries MAY be fully-developed entries, or MAY be
referrals generated from entries which have the referral object
class defined. Any attribute values which are received MUST be
displayed by the client. If a subordinate reference referral is
received, the client MUST restart the query, using the provided
data as the new search base. If any continuation reference
referrals are received, the client SHOULD start new queries for
each reference, and append the output of those queries to the
original query's output.
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5. Security Considerations
This document describes an application of the LDAPv3 protocol, and
as such it inherits the security considerations associated with
LDAPv3, as described in section 7 of RFC 2251.
By nature, LDAP is a read-write protocol, while the legacy WHOIS
service has always been a read-only service. As such, there are
significant risks associated with allowing unintended updates by
unauthorized third-parties. Moreover, allowing the LDAP-WHOIS
service to update the underlying delegation databases could result
in network resources being stolen from their lawful operators. For
example, if the LDAP front-end had update access to a domain
delegation database, a malicious third-party could theoretically
take ownership of that domain by exploiting an authentication
weakness, thereby causing ownership of the domain to be changed to
another party. For this reason, it is imperative that the LDAP-
WHOIS service not be allowed to make critical modifications to
delegated resources without ensuring that all possible precautions
have been taken.
The query processing models described in this document make use of
DNS lookups in order to locate the LDAP servers associated with a
particular resource. DNS is susceptible to certain attacks and
forgeries which may be used to redirect clients to LDAP servers
which are not authoritative for the resource in question.
Some operators may choose to purposefully provide misleading or
erroneous information in an effort to avoid responsibility for bad
behavior. In addition, there are likely to be sporadic operator
errors which will result in confusing or erroneous answers.
This document provides multiple query models which will cause the
same query to be answered by different servers (one would be
processed by a delegation entity, while another would be processed
by an operational entity). As a result, each of the servers may
provide different information, depending upon the query type that
was originally selected.
For all of the reasons listed above, it is essential that
applications and end-users not make critical decisions based on
the information provided by the LDAP-WHOIS service without having
reason to believe the veracity of the information. Users should
limit unknown or untrusted information to routine purposes.
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Finally, there are physical security issues associated with any
service which provides physical addressing and delivery
information. Although organizations are generally encouraged to
provide as much information as they feel comfortable with, no
information is required.
6. IANA Considerations
This document defines an application of the LDAPv3 protocol rather
than a new Internet application protocol. As such, there are no
protocol-related IANA considerations.
However, this document does define several LDAP schema elements,
including object classes, attributes, syntaxes and extensibleMatch
filters, and these elements should be assigned OID values from the
IANA branch, rather than being assigned from a particular
enterprise branch.
Finally, this document also describes several instances where
public DNS and LDAP servers are queried. It is expected that IANA
will establish and maintain these LDAP servers (and the necessary
DNS SRV domain names and resource records) required for this
service to operate. This includes providing SRV resource records
in the generic TLDs and the root domain, and also includes
administering the referenced LDAP servers.
7. Author's Addresses
Eric A. Hall
ehall@ehsco.com
8. References
RFC 2247 - Using Domains in LDAP/X.500 DNs
RFC 2251 - Lightweight Directory Access Protocol (v3)
RFC 2252 - Lightweight Directory Access Protocol (v3):
Attribute Syntax Definitions.
RFC 2254 - The String Representation of LDAP Search Filters
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Internet Draft draft-ietf-crisp-lw-asn-00.txt July 2002
[ir-dir-req] - <draft-newton-ir-dir-requirements-00.txt> -
Internet Registry Directory Requirements
[ldap-whois] - <draft-ietf-crisp-lw-core-00.txt> - The
Internet Resource Query Service and the Internet Resource
Schema
9. Acknowledgments
Portions of this work were funded by Network Solutions, Inc.
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