Network Working Group M. Daniele

Network Working Group M. Daniele
Request for Comments: 3291 Consultant
Obsoletes: 2851 B. Haberman
Category: Standards Track Consultant
S. Routhier
Wind River Systems, Inc.
J. Schoenwaelder
TU Braunschweig
May 2002

Textual Conventions for Internet Network Addresses

Status of this Memo

This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2002). All Rights Reserved.

Abstract

This MIB module defines textual conventions to represent commonly
used Internet network layer addressing information. The intent is
that these textual conventions (TCs) will be imported and used in MIB
modules that would otherwise define their own representations.

This document obsoletes RFC 2851.

Daniele, et. al. Standards Track [Page 1]

RFC 3291 TCs for Internet Network Addresses May 2002

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The SNMP Management Framework . . . . . . . . . . . . . . . . 4
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Usage Hints . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Table Indexing . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2 Uniqueness of Addresses . . . . . . . . . . . . . . . . . . . 12
4.3 Multiple Addresses per Host . . . . . . . . . . . . . . . . . 13
4.4 Resolving DNS Names . . . . . . . . . . . . . . . . . . . . . 13
5. Table Indexing Example . . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
8. Intellectual Property Notice . . . . . . . . . . . . . . . . . 16
9. Changes from RFC 2851 . . . . . . . . . . . . . . . . . . . . 16
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 20

1. Introduction

Several standards-track MIB modules use the IpAddress SMIv2 base
type. This limits the applicability of these MIB modules to IP
Version 4 (IPv4) since the IpAddress SMIv2 base type can only contain
4 byte IPv4 addresses. The IpAddress SMIv2 base type has become
problematic with the introduction of IP Version 6 (IPv6) addresses
[19].

This document defines multiple textual conventions as a mechanism to
express generic Internet network layer addresses within MIB module
specifications. The solution is compatible with SMIv2 (STD 58) and
SMIv1 (STD 16). New MIB definitions which need to express network
layer Internet addresses SHOULD use the textual conventions defined
in this memo. New MIB modules SHOULD NOT use the SMIv2 IpAddress
base type anymore.

A generic Internet address consists of two objects, one whose syntax
is InetAddressType, and another whose syntax is InetAddress. The
value of the first object determines how the value of the second
object is encoded. The InetAddress textual convention represents an
opaque Internet address value. The InetAddressType enumeration is
used to "cast" the InetAddress value into a concrete textual
convention for the address type. This usage of multiple textual
conventions allows expression of the display characteristics of each
address type and makes the set of defined Internet address types
extensible.

Daniele, et. al. Standards Track [Page 2]

RFC 3291 TCs for Internet Network Addresses May 2002

The textual conventions defined in this document can also be used to
represent generic Internet subnets and Internet address ranges. A
generic Internet subnet is represented by three objects, one whose
syntax is InetAddressType, a second one whose syntax is InetAddress
and a third one whose syntax is InetAddressPrefixLength. The
InetAddressType value again determines the concrete format of the
InetAddress value while the InetAddressPrefixLength identifies the
Internet network address prefix.

A generic range of consecutive Internet addresses is represented by
three objects. The first one has the syntax InetAddressType while
the remaining objects have the syntax InetAddress and specify the
start and end of the address range. The InetAddressType value again
determines the format of the InetAddress values.

The textual conventions defined in this document can be used to
define Internet addresses by using DNS domain names in addition to
IPv4 and IPv6 addresses. A MIB designer can write compliance
statements to express that only a subset of the possible address
types must be supported by a compliant implementation.

MIB developers who need to represent Internet addresses SHOULD use
these definitions whenever applicable, as opposed to defining their
own constructs. Even MIB modules that only need to represent IPv4 or
IPv6 addresses SHOULD use the InetAddressType/InetAddress textual
conventions defined in this memo.

There are many widely deployed MIB modules that use IPv4 addresses
and which need to be revised to support IPv6. These MIBs can be
categorized as follows:

1. MIB modules which define management information that is in
principle IP version neutral, but the MIB currently uses
addressing constructs specific to a certain IP version.

2. MIB modules which define management information that is specific
to particular IP version (either IPv4 or IPv6) and which is very
unlikely to ever be applicable to another IP version.

MIB modules of the first type SHOULD provide object definitions
(e.g., tables) that work with all versions of IP. In particular,
when revising a MIB module which contains IPv4 specific tables, it is
suggested to define new tables using the textual conventions defined
in this memo which support all versions of IP. The status of the new
tables SHOULD be "current" while the status of the old IP version
specific tables SHOULD be changed to "deprecated". The other
approach of having multiple similar tables for different IP versions
is strongly discouraged.

Daniele, et. al. Standards Track [Page 3]

RFC 3291 TCs for Internet Network Addresses May 2002

MIB modules of the second type, which are inherently IP version
specific, do not need to be redefined. Note that even in this case,
any additions to these MIB modules or new IP version specific MIB
modules SHOULD use the textual conventions defined in this memo.

MIB developers SHOULD NOT use the textual conventions defined in this
document to represent generic transport layer addresses. Instead the
SMIv2 TAddress textual convention and associated definitions should
be used for transport layer addresses.

The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT" and "MAY" in
this document are to be interpreted as described in RFC 2119 [1].

2. The SNMP Management Framework

The SNMP Management Framework presently consists of five major
components:

o An overall architecture, described in RFC 2571 [2].

o Mechanisms for describing and naming objects and events for the
purpose of management. The first version of this Structure of
Management Information (SMI) is called SMIv1 and described in STD
16, RFC 1155 [3], STD 16, RFC 1212 [4] and RFC 1215 [5]. The
second version, called SMIv2, is described in STD 58, RFC 2578
[6], STD 58, RFC 2579 [7] and STD 58, RFC 2580 [8].

o Message protocols for transferring management information. The
first version of the SNMP message protocol is called SNMPv1 and
described in STD 15, RFC 1157 [9]. A second version of the SNMP
message protocol, which is not an Internet standards track
protocol, is called SNMPv2c and described in RFC 1901 [10] and RFC
1906 [11]. The third version of the message protocol is called
SNMPv3 and described in RFC 1906 [11], RFC 2572 [12] and RFC 2574
[13].

o Protocol operations for accessing management information. The
first set of protocol operations and associated PDU formats is
described in STD 15, RFC 1157 [9]. A second set of protocol
operations and associated PDU formats is described in RFC 1905
[14].

o A set of fundamental applications described in RFC 2573 [15] and
the view-based access control mechanism described in RFC 2575
[16].

A more detailed introduction to the current SNMP Management Framework
can be found in RFC 2570 [17].

Daniele, et. al. Standards Track [Page 4]

RFC 3291 TCs for Internet Network Addresses May 2002

Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using the mechanisms defined in the SMI.

This memo specifies a MIB module that is compliant to the SMIv2. A
MIB conforming to the SMIv1 can be produced through the appropriate
translations. The resulting translated MIB must be semantically
equivalent, except where objects or events are omitted because no
translation is possible (use of Counter64). Some machine readable
information in SMIv2 will be converted into textual descriptions in
SMIv1 during the translation process. However, this loss of machine
readable information is not considered to change the semantics of the
MIB.

3. Definitions

INET-ADDRESS-MIB DEFINITIONS ::= BEGIN

IMPORTS
MODULE-IDENTITY, mib-2, Unsigned32 FROM SNMPv2-SMI
TEXTUAL-CONVENTION FROM SNMPv2-TC;

inetAddressMIB MODULE-IDENTITY
LAST-UPDATED "200205090000Z"
ORGANIZATION
"IETF Operations and Management Area"
CONTACT-INFO
"Juergen Schoenwaelder (Editor)
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig, Germany

Phone: +49 531 391-3289
EMail: [email protected]

Send comments to <[email protected]>."
DESCRIPTION
"This MIB module defines textual conventions for
representing Internet addresses. An Internet
address can be an IPv4 address, an IPv6 address
or a DNS domain name. This module also defines
textual conventions for Internet port numbers,
autonomous system numbers and the length of an
Internet address prefix."
REVISION "200205090000Z"
DESCRIPTION
"Second version, published as RFC 3291. This
revisions contains several clarifications and it

Daniele, et. al. Standards Track [Page 5]

RFC 3291 TCs for Internet Network Addresses May 2002

introduces several new textual conventions:
InetAddressPrefixLength, InetPortNumber,
InetAutonomousSystemNumber, InetAddressIPv4z,
and InetAddressIPv6z."
REVISION "200006080000Z"
DESCRIPTION
"Initial version, published as RFC 2851."
::= { mib-2 76 }

InetAddressType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A value that represents a type of Internet address.
unknown(0) An unknown address type. This value MUST
be used if the value of the corresponding
InetAddress object is a zero-length string.
It may also be used to indicate an IP address
which is not in one of the formats defined
below.

ipv4(1) An IPv4 address as defined by the
InetAddressIPv4 textual convention.

ipv6(2) A global IPv6 address as defined by the
InetAddressIPv6 textual convention.

ipv4z(3) A non-global IPv4 address including a zone
index as defined by the InetAddressIPv4z
textual convention.

ipv6z(4) A non-global IPv6 address including a zone
index as defined by the InetAddressIPv6z
textual convention.

dns(16) A DNS domain name as defined by the
InetAddressDNS textual convention.

Each definition of a concrete InetAddressType value must be
accompanied by a definition of a textual convention for use
with that InetAddressType.

To support future extensions, the InetAddressType textual
convention SHOULD NOT be sub-typed in object type definitions.
It MAY be sub-typed in compliance statements in order to
require only a subset of these address types for a compliant
implementation.

Implementations must ensure that InetAddressType objects

Daniele, et. al. Standards Track [Page 6]

RFC 3291 TCs for Internet Network Addresses May 2002

and any dependent objects (e.g. InetAddress objects) are
consistent. An inconsistentValue error must be generated
if an attempt to change an InetAddressType object would,
for example, lead to an undefined InetAddress value. In
particular, InetAddressType/InetAddress pairs must be
changed together if the address type changes (e.g. from
ipv6(2) to ipv4(1))."
SYNTAX INTEGER {
unknown(0),
ipv4(1),
ipv6(2),
ipv4z(3),
ipv6z(4),
dns(16)
}

InetAddress ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Denotes a generic Internet address.

An InetAddress value is always interpreted within the context
of an InetAddressType value. Every usage of the InetAddress
textual convention is required to specify the InetAddressType
object which provides the context. It is suggested that the
InetAddressType object is logically registered before the
object(s) which use the InetAddress textual convention if
they appear in the same logical row.

The value of an InetAddress object must always be
consistent with the value of the associated InetAddressType
object. Attempts to set an InetAddress object to a value
which is inconsistent with the associated InetAddressType
must fail with an inconsistentValue error.

When this textual convention is used as the syntax of an
index object, there may be issues with the limit of 128
sub-identifiers specified in SMIv2, STD 58. In this case,
the object definition MUST include a 'SIZE' clause to
limit the number of potential instance sub-identifiers."
SYNTAX OCTET STRING (SIZE (0..255))

InetAddressIPv4 ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1d.1d.1d.1d"
STATUS current
DESCRIPTION
"Represents an IPv4 network address:

Daniele, et. al. Standards Track [Page 7]

RFC 3291 TCs for Internet Network Addresses May 2002

octets contents encoding
1-4 IPv4 address network-byte order

The corresponding InetAddressType value is ipv4(1).

This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific format.
However, if it is used, it MAY be used either on its own or in
conjunction with InetAddressType as a pair."
SYNTAX OCTET STRING (SIZE (4))

InetAddressIPv6 ::= TEXTUAL-CONVENTION
DISPLAY-HINT "2x:2x:2x:2x:2x:2x:2x:2x"
STATUS current
DESCRIPTION
"Represents an IPv6 network address:

octets contents encoding
1-16 IPv6 address network-byte order

The corresponding InetAddressType value is ipv6(2).

This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific format.
However, if it is used, it MAY be used either on its own or in
conjunction with InetAddressType as a pair."
SYNTAX OCTET STRING (SIZE (16))

InetAddressIPv4z ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1d.1d.1d.1d%4d"
STATUS current
DESCRIPTION
"Represents a non-global IPv4 network address together
with its zone index:

octets contents encoding
1-4 IPv4 address network-byte order
5-8 zone index network-byte order

The corresponding InetAddressType value is ipv4z(3).

The zone index (bytes 5-8) is used to disambiguate identical
address values on nodes which have interfaces attached to
different zones of the same scope. The zone index may contain
the special value 0 which refers to the default zone for each
scope.

This textual convention SHOULD NOT be used directly in object

Daniele, et. al. Standards Track [Page 8]

RFC 3291 TCs for Internet Network Addresses May 2002

definitions since it restricts addresses to a specific format.
However, if it is used, it MAY be used either on its own or in
conjunction with InetAddressType as a pair."
SYNTAX OCTET STRING (SIZE (8))

InetAddressIPv6z ::= TEXTUAL-CONVENTION
DISPLAY-HINT "2x:2x:2x:2x:2x:2x:2x:2x%4d"
STATUS current
DESCRIPTION
"Represents a non-global IPv6 network address together
with its zone index:

octets contents encoding
1-16 IPv6 address network-byte order
17-20 zone index network-byte order

The corresponding InetAddressType value is ipv6z(4).

The zone index (bytes 17-20) is used to disambiguate
identical address values on nodes which have interfaces
attached to different zones of the same scope. The zone index
may contain the special value 0 which refers to the default
zone for each scope.

This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific format.
However, if it is used, it MAY be used either on its own or in
conjunction with InetAddressType as a pair."
SYNTAX OCTET STRING (SIZE (20))

InetAddressDNS ::= TEXTUAL-CONVENTION
DISPLAY-HINT "255a"
STATUS current
DESCRIPTION
"Represents a DNS domain name. The name SHOULD be fully
qualified whenever possible.

The corresponding InetAddressType is dns(16).

The DESCRIPTION clause of InetAddress objects that may have
InetAddressDNS values must fully describe how (and when) such
names are to be resolved to IP addresses.

This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific format.
However, if it is used, it MAY be used either on its own or in
conjunction with InetAddressType as a pair."
SYNTAX OCTET STRING (SIZE (1..255))

Daniele, et. al. Standards Track [Page 9]

RFC 3291 TCs for Internet Network Addresses May 2002

InetAddressPrefixLength ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Denotes the length of a generic Internet network address
prefix. A value of n corresponds to an IP address mask
which has n contiguous 1-bits from the most significant
bit (MSB) and all other bits set to 0.

An InetAddressPrefixLength value is always interpreted within
the context of an InetAddressType value. Every usage of the
InetAddressPrefixLength textual convention is required to
specify the InetAddressType object which provides the
context. It is suggested that the InetAddressType object is
logically registered before the object(s) which use the
InetAddressPrefixLength textual convention if they appear in
the same logical row.

InetAddressPrefixLength values that are larger than
the maximum length of an IP address for a specific
InetAddressType are treated as the maximum significant
value applicable for the InetAddressType. The maximum
significant value is 32 for the InetAddressType
'ipv4(1)' and 'ipv4z(3)' and 128 for the InetAddressType
'ipv6(2)' and 'ipv6z(4)'. The maximum significant value
for the InetAddressType 'dns(16)' is 0.

The value zero is object-specific and must be defined as
part of the description of any object which uses this
syntax. Examples of the usage of zero might include
situations where the Internet network address prefix
is unknown or does not apply."
SYNTAX Unsigned32

InetPortNumber ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Represents a 16 bit port number of an Internet transport
layer protocol. Port numbers are assigned by IANA. A
current list of all assignments is available from
<http://www.iana.org/>.

The value zero is object-specific and must be defined as
part of the description of any object which uses this
syntax. Examples of the usage of zero might include
situations where a port number is unknown, or when the
value zero is used as a wildcard in a filter."
REFERENCE "STD 6 (RFC 768), STD 7 (RFC 793) and RFC 2960"
SYNTAX Unsigned32 (0..65535)

Daniele, et. al. Standards Track [Page 10]

RFC 3291 TCs for Internet Network Addresses May 2002

InetAutonomousSystemNumber ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Represents an autonomous system number which identifies an
Autonomous System (AS). An AS is a set of routers under a
single technical administration, using an interior gateway
protocol and common metrics to route packets within the AS,
and using an exterior gateway protocol to route packets to
other ASs'. IANA maintains the AS number space and has
delegated large parts to the regional registries.

Autonomous system numbers are currently limited to 16 bits
(0..65535). There is however work in progress to enlarge the
autonomous system number space to 32 bits. This textual
convention therefore uses an Unsigned32 value without a
range restriction in order to support a larger autonomous
system number space."
REFERENCE "RFC 1771, RFC 1930"
SYNTAX Unsigned32

END

4. Usage Hints

The InetAddressType and InetAddress textual conventions have been
introduced to avoid over-constraining an object definition by the use
of the IpAddress SMI base type which is IPv4 specific. An
InetAddressType/InetAddress pair can represent IP addresses in
various formats.

The InetAddressType and InetAddress objects SHOULD NOT be sub-typed
in object definitions. Sub-typing binds the MIB module to specific
address formats, which may cause serious problems if new address
formats need to be introduced. Note that it is possible to write
compliance statements in order to express that only a subset of the
defined address types must be implemented to be compliant.

Every usage of the InetAddress or InetAddressPrefixLength textual
conventions must specify which InetAddressType object provides the
context for the interpretation of the InetAddress or
InetAddressPrefixLength textual convention.

It is suggested that the InetAddressType object is logically
registered before the object(s) which uses the InetAddress or
InetAddressPrefixLength textual convention. An InetAddressType
object is logically registered before an InetAddress or
InetAddressPrefixLength object if it appears before the InetAddress
or InetAddressPrefixLength object in the conceptual row (which

Daniele, et. al. Standards Track [Page 11]

RFC 3291 TCs for Internet Network Addresses May 2002

includes any index objects). This rule allows programs such as MIB
compilers to identify the InetAddressType of a given InetAddress or
InetAddressPrefixLength object by searching for the InetAddressType
object which precedes an InetAddress or InetAddressPrefixLength
object.

4.1 Table Indexing

When a generic Internet address is used as an index, both the
InetAddressType and InetAddress objects MUST be used. The
InetAddressType object MUST be listed before the InetAddress object
in the INDEX clause.

The IMPLIED keyword MUST NOT be used for an object of type
InetAddress in an INDEX clause. Instance sub-identifiers are then of
the form T.N.O1.O2...On, where T is the value of the InetAddressType
object, O1...On are the octets in the InetAddress object, and N is
the number of those octets.

There is a meaningful lexicographical ordering to tables indexed in
this fashion. Command generator applications may lookup specific
addresses of known type and value, issue GetNext requests for
addresses of a single type, or issue GetNext requests for a specific
type and address prefix.

4.2 Uniqueness of Addresses

IPv4 addresses were intended to be globally unique, current usage
notwithstanding. IPv6 addresses were architected to have different
scopes and hence uniqueness [19]. In particular, IPv6 "link-local"
and "site-local" addresses are not guaranteed to be unique on any
particular node. In such cases, the duplicate addresses must be
configured on different interfaces. So the combination of an IPv6
address and a zone index is unique [21].

The InetAddressIPv6 textual convention has been defined to represent
global IPv6 addresses and non-global IPv6 addresses in cases where no
zone index is needed (e.g., on end hosts with a single interface).
The InetAddressIPv6z textual convention has been defined to represent
non-global IPv6 addresses in cases where a zone index is needed
(e.g., a router connecting multiple zones). MIB designers who use
InetAddressType/InetAddress pairs therefore do not need to define
additional objects in order to support non-global addresses on nodes
that connect multiple zones.

The InetAddressIPv4z is intended for use in MIBs (like the TCP-MIB)
which report addresses in the address family used on the wire, but
where the entity instrumented obtains such addresses from

Daniele, et. al. Standards Track [Page 12]

RFC 3291 TCs for Internet Network Addresses May 2002

applications or administrators in a form which includes a zone index,
such as v4-mapped IPv6 addresses.

The size of the zone index has been chosen so that it is consistent
with (i) the numerical zone index defined in [21] and (ii) the
sin6_scope_id field of the sockaddr_in6 structure defined in RFC 2553
[20].

4.3 Multiple Addresses per Host

A single host system may be configured with multiple addresses (IPv4
or IPv6), and possibly with multiple DNS names. Thus it is possible
for a single host system to be accessible by multiple
InetAddressType/InetAddress pairs.

If this could be an implementation or usage issue, the DESCRIPTION
clause of the relevant objects must fully describe which address is
reported in a given InetAddressType/InetAddress pair.

4.4 Resolving DNS Names

DNS names MUST be resolved to IP addresses when communication with
the named host is required. This raises a temporal aspect to
defining MIB objects whose value is a DNS name: When is the name
translated to an address?

For example, consider an object defined to indicate a forwarding
destination, and whose value is a DNS name. When does the forwarding
entity resolve the DNS name? Each time forwarding occurs or just
once when the object was instantiated?

The DESCRIPTION clause of such objects SHOULD precisely define how
and when any required name to address resolution is done.

Similarly, the DESCRIPTION clause of such objects SHOULD precisely
define how and when a reverse lookup is being done if an agent has
accessed instrumentation that knows about an IP address and the MIB
module or implementation requires it to map the IP address to a DNS
name.

5. Table Indexing Example

This example shows a table listing communication peers that are
identified by either an IPv4 address, an IPv6 address or a DNS name.
The table definition also prohibits entries with an empty address
(whose type would be "unknown"). The size of a DNS name is limited
to 64 characters in order to satisfy OID length constraints.

Daniele, et. al. Standards Track [Page 13]

RFC 3291 TCs for Internet Network Addresses May 2002

peerTable OBJECT-TYPE
SYNTAX SEQUENCE OF PeerEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of communication peers."
::= { somewhere 1 }

peerEntry OBJECT-TYPE
SYNTAX PeerEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry containing information about a particular peer."
INDEX { peerAddressType, peerAddress }
::= { peerTable 1 }

PeerEntry ::= SEQUENCE {
peerAddressType InetAddressType,
peerAddress InetAddress,
peerStatus INTEGER
}

peerAddressType OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The type of Internet address by which the peer
is reachable."
::= { peerEntry 1 }

peerAddress OBJECT-TYPE
SYNTAX InetAddress (SIZE (1..64))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The Internet address for the peer. The type of this
address is determined by the value of the peerAddressType
object. Note that implementations must limit themselves
to a single entry in this table per reachable peer.
The peerAddress may not be empty due to the SIZE
restriction.

Daniele, et. al. Standards Track [Page 14]

RFC 3291 TCs for Internet Network Addresses May 2002

If a row is created administratively by an SNMP
operation and the address type value is dns(16), then
the agent stores the DNS name internally. A DNS name
lookup must be performed on the internally stored DNS
name whenever it is being used to contact the peer.

If a row is created by the managed entity itself and
the address type value is dns(16), then the agent
stores the IP address internally. A DNS reverse lookup
must be performed on the internally stored IP address
whenever the value is retrieved via SNMP."
::= { peerEntry 2 }

The following compliance statement specifies that compliant
implementations need only support IPv4/IPv6 addresses without a zone
indices. Support for DNS names or IPv4/IPv6 addresses with zone
indices is not required.

peerCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement of the peer MIB."

MODULE -- this module
MANDATORY-GROUPS { peerGroup }

OBJECT peerAddressType
SYNTAX InetAddressType { ipv4(1), ipv6(2) }
DESCRIPTION
"An implementation is only required to support IPv4
and IPv6 addresses without zone indices."

::= { somewhere 2 }

Note that the SMIv2 does not permit inclusion of not-accessible
objects in an object group (see section 3.1 in STD 58, RFC 2580 [8]).
It is therefore not possible to formally refine the syntax of
auxiliary objects which are not-accessible. In such a case, it is
suggested to express the refinement informally in the DESCRIPTION
clause of the MODULE-COMPLIANCE macro invocation.

Daniele, et. al. Standards Track [Page 15]

RFC 3291 TCs for Internet Network Addresses May 2002

6. Security Considerations

This module does not define any management objects. Instead, it
defines a set of textual conventions which may be used by other MIB
modules to define management objects.

Meaningful security considerations can only be written in the MIB
modules that define management objects. This document has therefore
no impact on the security of the Internet.

7. Acknowledgments

This document was produced by the Operations and Management Area
"IPv6MIB" design team. The authors would like to thank Fred Baker,
Randy Bush, Richard Draves, Mark Ellison, Bill Fenner, Jun-ichiro
Hagino, Mike Heard, Tim Jenkins, Glenn Mansfield, Keith McCloghrie,
Thomas Narten, Erik Nordmark, Peder Chr. Norgaard, Randy Presuhn,
Andrew Smith, Dave Thaler, Kenneth White, Bert Wijnen, and Brian Zill
for their comments and suggestions.

8. Intellectual Property Notice

The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP 11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.

9. Changes from RFC 2851

The following changes have been made relative to RFC 2851:

o Added new textual conventions InetAddressPrefixLength,
InetPortNumber, and InetAutonomousSystemNumber.

Daniele, et. al. Standards Track [Page 16]

RFC 3291 TCs for Internet Network Addresses May 2002

o Rewrote the introduction to say clearly that in general, one
should define MIB tables that work with all versions of IP. The
other approach of multiple tables for different IP versions is
strongly discouraged.

o Added text to the InetAddressType and InetAddress descriptions
which requires that implementations must reject set operations
with an inconsistentValue error if they lead to inconsistencies.

o Removed the strict ordering constraints. Description clauses now
must explain which InetAddressType object provides the context for
an InetAddress or InetAddressPrefixLength object.

o Aligned wordings with the IPv6 scoping architecture document.

o Split the InetAddressIPv6 textual convention into the two textual
conventions (InetAddressIPv6 and InetAddressIPv6z) and introduced
a new textual convention InetAddressIPv4z. Added ipv4z(3) and
ipv6z(4) named numbers to the InetAddressType enumeration.
Motivations for this change: (i) enable the introduction of a
textual conventions for non-global IPv4 addresses, (ii) alignment
with the textual conventions for transport addresses, (iii)
simpler compliance statements in cases where support for IPv6
addresses with zone indices is not required, (iv) simplify
implementations for host systems which will never have to report
zone indices.

References

[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.

[2] Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for
Describing SNMP Management Frameworks", RFC 2571, April 1999.

[3] Rose, M. and K. McCloghrie, "Structure and Identification of
Management Information for TCP/IP-based Internets", STD 16, RFC
1155, May 1990.

[4] Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD 16,
RFC 1212, March 1991.

[5] Rose, M., "A Convention for Defining Traps for use with the
SNMP", RFC 1215, March 1991.

[6] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
M. and S. Waldbusser, "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.

Daniele, et. al. Standards Track [Page 17]

RFC 3291 TCs for Internet Network Addresses May 2002

[7] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
M. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58,
RFC 2579, April 1999.

[8] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
M. and S. Waldbusser, "Conformance Statements for SMIv2", STD
58, RFC 2580, April 1999.

[9] Case, J., Fedor, M., Schoffstall, M. and J. Davin, "A Simple
Network Management Protocol (SNMP)", STD 15, RFC 1157, May 1990.

[10] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
"Introduction to Community-based SNMPv2", RFC 1901, January
1996.

[11] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport
Mappings for Version 2 of the Simple Network Management Protocol
(SNMPv2)", RFC 1906, January 1996.

[12] Case, J., Harrington, D., Presuhn, R. and B. Wijnen, "Message
Processing and Dispatching for the Simple Network Management
Protocol (SNMP)", RFC 2572, April 1999.

[13] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM)
for version 3 of the Simple Network Management Protocol
(SNMPv3)", RFC 2574, April 1999.

[14] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Protocol
Operations for Version 2 of the Simple Network Management
Protocol (SNMPv2)", RFC 1905, January 1996.

[15] Levi, D., Meyer, P. and B. Stewart, "SNMP Applications", RFC
2573, April 1999.

[16] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based Access
Control Model (VACM) for the Simple Network Management Protocol
(SNMP)", RFC 2575, April 1999.

[17] Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction
to Version 3 of the Internet-standard Network Management
Framework", RFC 2570, April 1999.

[18] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB",
RFC 2863, June 2000.

[19] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 2373, July 1998.

Daniele, et. al. Standards Track [Page 18]

RFC 3291 TCs for Internet Network Addresses May 2002

[20] Gilligan, R., Thomson, S., Bound, J. and W. Stevens, "Basic
Socket Interface Extensions for IPv6", RFC 2553, March 1999.

[21] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., Onoe, A.
and B. Zill, "IPv6 Scoped Address Architecture", Work in
Progress.

Authors' Addresses

Mike Daniele
Consultant
19 Pinewood Rd
Hudson, NH 03051
USA

Phone: +1 603 883-6365
EMail: [email protected]

Brian Haberman

Phone: +1 919 949-4828
EMail: [email protected]

Shawn A. Routhier
Wind River Systems, Inc.
500 Wind River Way
Alameda, CA 94501
USA

Phone: +1 510 749 2095
EMail: [email protected]

Juergen Schoenwaelder
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig
Germany

Phone: +49 531 391-3289
EMail: [email protected]

Daniele, et. al. Standards Track [Page 19]

RFC 3291 TCs for Internet Network Addresses May 2002

Full Copyright Statement

Copyright (C) The Internet Society (2002). All Rights Reserved.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.

Daniele, et. al. Standards Track [Page 20]