Internet Draft J. Quittek
Document: draft-stiemerling-midcom-mib-00.txt M. Stiemerling
Expires: April 2003 NEC Europe Ltd.
October 2003
Definitions of Managed Objects for Middlebox Communication
<draft-stiemerling-midcom-mib-00.txt>
Status of this Memo
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in the Internet community.
In particular, it describes a set of managed objects that allow
configuring middleboxes, such as firewalls and network address
translators, in order to enable communication across these devices.
The definitions of managed objects in this documents follows closely
the MIDCOM semantics defined in RFC XXXX.
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Table of Contents
1 Introduction ................................................. 2
2 The Internet-Standard Management Framework ................... 2
3 Overview ..................................................... 2
3.1 Terminology ................................................ 3
4 Realizing the MIDCOM Protocol with SNMP ...................... 3
4.1 MIDCOM Sessions ............................................ 3
4.1.1 Authentication and Authorization ......................... 4
4.2 MIDCOM Transactions ........................................ 4
4.2.1 Asynchronous Transactions ................................ 4
4.2.2 Configuration Transactions ............................... 6
4.2.3 Configuration Transactions ............................... 8
4.2.4 Atomicity or Transactions ................................ 10
4.2.4.1 Asynchronous Transactions .............................. 10
4.2.4.2 Session Establishment and Termination Transactions ..... 10
4.2.4.3 Monitoring Transactions ................................ 10
4.2.4.4 Lifetime Change Transactions ........................... 11
4.2.4.5 Transactions Establishing New Policy Rules ............. 11
4.2.5 Access Control ........................................... 11
4.3 Access Control Policies .................................... 11
5 Structure of the MIB module .................................. 12
5.1 midcomCapabilities ......................................... 12
5.2 midcomSessionTable ......................................... 13
5.3 midcomRuleTable ............................................ 14
5.4 midcomGroupTable ........................................... 16
5.5 midcomEvent ................................................ 17
6 Definitions .................................................. 17
7 Usage Examples ............................................... 42
7.1 Session Establishment (SE) ................................. 43
7.2 Session Termination (ST) ................................... 44
7.3 Asynchronous Session Termination (AST) ..................... 44
7.4 Policy Reserve Rule (PRR) .................................. 44
7.5 Policy Enable Rule (PER) after PRR ......................... 45
7.6 Policy Enable Rule (PER) without previous PRR .............. 46
7.7 Policy Rule Lifetime Change (RLC) .......................... 47
7.8 Policy Rule List (PRL) ..................................... 47
7.9 Policy Rule Status (PRS) ................................... 47
7.10 Asynchronous Policy Rule Event (ARE) ...................... 47
7.11 Group Lifetime Change (GLC) ............................... 48
7.12 Group List (GL) ........................................... 48
7.13 Group Status (GS) ......................................... 48
7.14 Using Notifications For Negative Replies Only ............. 48
7.15 Not Using Notifications For Replies ....................... 48
8 Security Considerations ...................................... 49
9 Open Issues .................................................. 49
10 Normative References ........................................ 49
11 Informative References ...................................... 50
12 Authors' Addresses .......................................... 51
13 Full Copyright Statement .................................... 51
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1. Introduction
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in the Internet community.
In particular, it describes a set of managed objects that allow
monitoring of running instances of robust header compression.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119].
2. The Internet-Standard Management Framework
For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58,
RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
[RFC2580].
3. Overview
The managed objects defined in this document serve for controlling
firewalls and Network Address Translators (NATs). As defined in
[RFC3234], firewalls and NATs belong to the group of middleboxes. A
middlebox is a device on the datagram path between source and
destination, which performs other functions than just IP routing. As
outlined in [RFC3303], firewalls and NATs are potential obstacles to
packet streams, for example if dynamically negotiated UDP or TCP port
numbers are used, as in many peer-to-peer communication applications.
As one possible solution for this problem, the IETF MIDCOM working
group defined a framework [RFC3303], requirements [RFC3304] and
protocol semantics [RFCXXXX] for communication between applications
and middleboxes acting as firewalls, NATs or a combination of both.
The managed objects defined in this document can be used for
dynamically configuring middleboxes on the datagram path in order to
enable datagram streams to pass the middlebox. This way,
applications can request pinholes at firewalls and address bindings
at NATs.
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Since firewalls and NATs are critical devices concerning network
security, security issues of middlebox communication need to be
considered very carefully.
3.1. Terminology
The terminology used in this document is fully aligned with the
terminology defined in [RFCXXXX].
There is a conflict between the MIDCOM terminology and the SNMP
terminology. The roles of entities participating in SNMP
communication are called 'manager' and 'agent' with the agent acting
as server for requests from the manager. This use of the term 'agent'
is different to its use in the MIDCOM framework: The SNMP manager
corresponds to the MIDCOM agent and the SNMP agent corresponds to the
MIDCOM middlebox. In order to avoid confusion, the term agent is
only used in combination with a prefix: either as MIDCOM agent or as
SNMP agent.
As also mentioned in RFCXXXX, please note that ... bindings!!
4. Realizing the MIDCOM Protocol with SNMP
In order to realize middlebox communication as described in RFC XXXX,
several aspects and properties of the MIDCOM protocol need to be
mapped to SNMP capabilities and expressed in terms of the Structure
of Management Information version 2 (SMIv2).
Basic concepts to be mapped are MIDCOM sessions and MIDCOM
transactions. For both, access control policies need to be
supported.
4.1. MIDCOM Sessions
SNMP has no direct support for sessions. Therefore, they need to be
modeled. A session is stateful and has a context that is valid for
several transactions. For SNMP, a context is valid for a single
transaction only, for example covering just a single request/reply
pair of messages.
Properties of sessions that are utlized by the MIDCOM semantics and
not avaiable in SNMP need to be modeled. Particularly, the middlebox
needs to be able to send notification messages to agents
participating in a session.
The midcomSessionTable described in more detail in Section 5.1
provides this information. Each MIDCOM agent that opens a session
has to create an entry in the midcomSessionTable. This entry
identifies the MIDCOM agent as participant of a session and gives the
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middlebox sufficient information for sending notifications. The
MIDCOM-MIB module requires a MIDCOM agent to create an entry in the
midcomSessionTable before it creates or modifies MIDCOM policy rules.
Without creating an entry in the session table, the MIDCOM agent
cannot access any MIDCOM policy rule and it will not receive any
notification indicating state changes at the middlebox.
4.1.1. Authentication and Authorization
MIDCOM sessions are required to provide authentication, authorization
and encryption for messages exchanged between MIDCOM agent and
middlebox. SNMPv3 provides these features on a per-message basis
instead of a per-session basis. This more fine-grained security
based on the User-based Security Model (USM, [RFC3414]) providing
authentication and the View-based Access control Model (VACM,
[RFC3415]) that can be used for authorization of access to managed
objects. This can be considered as overhead compared to per-session
security mechanisms, but it completely satisfies the security
requirements of middlebox communication.
Any MIDCOM agent that wants to start a session by creating an entry
in the session table needs to authenticate itself as an SNMP user.
For the authenticated user, access rights must be given as part of
the VACM configuration of the SNMP agent.
4.2. MIDCOM Transactions
RFCXXXX defines the MIDCOM protocol semantics in terms of
transactions and transaction parameters. Transactions are grouped
into request-reply transactions and asynchronous transactions.
SNMP offers simple transactions that in general cannot be mapped ono-
to-one to MIDCOM transactions. This section describes how the MIDCOM
MIB module implements MIDCOM transactions using SNMP transactions.
The concerned MIDCOM transactions are asynchronous transactions a and
request-reply transactions. Within the set of request-reply
transactions we distinguish configuration transactions and monitoring
transactions, because they are implemented in slightly different ways
by using SNMP transactions.
4.2.1. Asynchronous Transactions
Asynchronous transactions can easily be modeled by SNMP
notifications. An asynchronous transaction contains a notification
message with one to three parameters. The message can be realized as
an SNMP notification with the parameters implemented as managed
objects contained in the notification.
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+--------------+ notification +------------+
| MIDCOM agent |<--------------| middlebox |
+--------------+ message +------------+
MIDCOM asynchronous transaction
+--------------+ SNMP +------------+
| SNMP manager |<--------------| SNMP agent |
+--------------+ notification +------------+
Implementation of MIDCOM asynchronous transaction
Figure 1: MIDCOM asynchronous transaction
mapped to SNMP notification
One of the parameters is the transaction identifier that should be
unique per middlebox. It does not have to be unique for all
notifications sent by the particular SNMP agent, but for all sent
notifications that are defined by the MIDCOM MIB module.
4.2.2. Configuration Transactions
All request-reply transactions contain a request message, a reply
message and potentially also a set of notifications. In general they
cannot be modeled by just having one SNMP message per MIDCOM message,
because some of the MIDCOM messages carry a large set of parameters
that do not necessarily fit into an SNMP message consisting of a
single UDP packet only.
For configuration transactions the MIDCOM request message can be
modeled by one or more SNMP set transactions. The action of sending
the MIDCOM request to the middlebox if realized by writing the
parameters contained in the message to managed objects at the SNMP
agent. If necessary, the SNMP set transaction includes creating
these managed objects. If not all parameters of the MIDCOM request
message can be set by a single SNMP set transaction, then more than
one set transactions are used, see Figure 2. The last one of these
messages must clearly indicate that now all parameters are set and
that processing of the MIDCOM request message can start at the
middlebox.
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+--------------+ request +------------+
| MIDCOM agent |-------------->| middlebox |
+--------------+ message +------------+
MIDCOM request message
+--------------+ +------------+
| | SNMP set | |
| |-------------->| |
| | message | |
| | | |
| | SNMP set | |
| |<--------------| |
| | reply message | |
| SNMP manager | | SNMP agent |
| | SNMP set | |
| |- - - - - - - >| |
| | message | |
| | | |
| | SNMP set | |
| |< - - - - - - -| |
| | reply message | |
| | | |
| | . . . | |
+--------------+ +------------+
Implementation of MIDCOM request message
by one or more SNMP set messages
Figure 2: MIDCOM request message
mapped to SNMP set transactions
Please note that a single SNMP set transaction consists of an SNMP
set request message and an SNMP set reply message. Both are sent as
unreliable UDP packets and may be dropped before they reach their
destination. If the SNMP set request message is lost, then the SNMP
agent repeats the message after receiving no reply for a specified
time. Also if the SNMP set reply message is lost, the SNMP agent
retransmit the SNMP set message. But this time, the SNMP agent
receives the same message twice and must make sure that it accepts
the second message as it did the first one and that it sends an SNMP
reply message again.
The MIDCOM reply message can be modeled by an SNMP norification
transaction optionally followed by one or more SNMP get transactions
as shown in Figure 3. The SNMP agent informs the SNMP manager about
the end of processing the request by sending an SNMP notification.
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If possible, the SNMP notification carries all reply parameters. If
this is not possible, then the SNMP manager has to perform additional
SNMP get transactions as long as is needed to receive all of the
reply parameters.
+--------------+ reply +------------+
| MIDCOM agent |<--------------| middlebox |
+--------------+ message +------------+
MIDCOM reply message
+--------------+ +------------+
| | SNMP | |
| |<--------------| |
| | notification | |
| | | |
| | SNMP get | |
| |-------------->| |
| | message | |
| SNMP manager | | SNMP agent |
| | SNMP get | |
| |<--------------| |
| | reply message | |
| | | |
| | SNMP get | |
| |- - - - - - - >| |
| | message | |
| | | |
| | SNMP get | |
| |< - - - - - - -| |
| | reply message | |
| | | |
| | . . . | |
+--------------+ +------------+
Implementation of MIDCOM reply message
by an SNMP notification
and one or more SNMP set messages
Figure 3: MIDCOM reply message
mapped to SNMP notification and optional get transactions
4.2.3. Configuration Transactions
The realization of MIDCOM monitoring transactions in terms of SNMP
transactions is simpler. The request message is very short and just
specifies a piece of information that the MIDCOM agent wants to
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retrieve.
Since monitoring is the stronghold of SNMP, there are sufficient
means to realize MIDCOM monitoring transactions simpler than MIDCOM
configuration transactions.
All MIDCOM monitoring transactions can be realized as a sequence of
SNMP get transactions. If one or more SNMP get transactions are
required depends on the amount of information that is to be
retrieved.
+--------------+ request +------------+
| |-------------->| |
| | message | |
| MIDCOM agent | | middlebox |
| | reply | |
| |<--------------| |
+--------------+ message +------------+
MIDCOM monitoring transaction
+--------------+ +------------+
| | SNMP get | |
| |-------------->| |
| | message | |
| | | |
| | SNMP get | |
| |<--------------| |
| | reply message | |
| SNMP manager | | SNMP agent |
| | SNMP get | |
| |- - - - - - - >| |
| | message | |
| | | |
| | SNMP get | |
| |< - - - - - - -| |
| | reply message | |
| | | |
| | . . . | |
+--------------+ +------------+
Implementation of MIDCOM monitoring transaction
by one or more SNMP get messages
Figure 4: MIDCOM monitoring transaction
mapped to SNMP get transactions
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4.2.4. Atomicity or Transactions
Given the realizations of MIDCOM transactions by means of SNMP
transactions, atomicity of the MIDCOM transactions is not guaranteed
anymore. Therefore, we analyze the potential loss of atomicity for
each MIDCOM transaction.
4.2.4.1. Asynchronous Transactions
There are two asynchronous MIDCOM transactions: Asynchronous Session
Termination (AST) and Asynchronous policy Rule Event (ARE). For both
atomicity is maintained, because each of them is modeled by a single
atomic SNMP notification transaction.
4.2.4.2. Session Establishment and Termination Transactions
For the Session Establishment (SE) transaction and the Session
Termination (ST) atomicity is maintained. The ST transaction has
very few parameters. The request parameters can be transmitted by a
single SNMP set request message and the reply parameters can be
transmitted by a single SNMP notifications message.
Basically, the same holds for SE, but it needs more explanations.
The SE transaction include the optional transmission of
authentication challenges and authentication replies. These are not
required if SNMPv3 is used, because SNMPv3 provides all required
means for authentication. Also, the SE transaction includes
tranmission of middlebox capabilities from the middlebox to the
agent. But for this transmission, there is no atomicity requirement,
because these capabilities are static and can be transmitted piece by
piece.
Therefore, the SE transaction is implemented by an SNMP set
transaction modeling the request message and an SNMP notification
transaction modeling the reply message excluding the transfer of
middlebox capabilities. In the MIDCOM MIB module the middlebox
capabilities are provided by a set of managed objects that can be
read by the MIDCOM agent at any time using SNMP get transactions.
4.2.4.3. Monitoring Transactions
For the monitoring transactions Policy Rule List (PRL), Policy Rule
Status (PRS) Group List (GL) und Group Status (GS) atomicity is not
given anymore, because they are implemented by potentially more than
one SNMP get operations. The potential problem is that while the
monitoring transaction is performed, the monitored items may change.
For example, while reading a long list of policies, new policies may
be added and already read policies may be deleted. This is not in
line with the protcol semantics. However, it is acceptable because
it i not in conflict with the MIDCOM requirement requesting the
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middlebox state to be stable and known by the MIDCOM agent, because
the middlebox notifies the MIDCOM agent on all changes to its state
that are performed during the monitoring transaction by sending
notifications. The MIDCOM agent can then either repeat the
monitoring transaction or integrate the result of the monitoring
transaction with the information received via notifications during
the transaction. In both cases, the MIDCOM agent will finally know
the state of the middlebox.
4.2.4.4. Lifetime Change Transactions
For the policy Rule Lifetime Change (RLC) transaction and the Group
Lifetime Change (GLC) transaction atomicity is maintained. They both
have very few parameters for request message and reply message. The
request parameters can be transmitted by a single SNMP set request
message and the reply parameters can be transmitted by a single SNMP
notifications message.
4.2.4.5. Transactions Establishing New Policy Rules
To be done: Discuss atomicity of PRR and PER.
4.2.5. Access Control
Since SNMP does not offer per-session authentication and
authorization, authentication and authorization are performed per
SNMP message sent from the MIDCOM agent to the middlebox.
For each transaction, the MIDCOM agent has to authenticate itself as
an SNMP user according to USM. Then the user's access rights to all
resources affected by the transaction are checked. Access right
control is realized by configuring the VACM mechanisms at the SNMP
agent.
4.3. Access Control Policies
Potentially, a middlebox has to control access for a large set of
agents and to a large set of policy rules configuring firewall
pinholes and NAT bindings. Therefore it can be beneficial to use
access control policies for specifying access control rules.
Generating, provisioning and managing these policies is out of scope
of this MIB module.
However, if such access control policy system is used, then the SNMP
agent acts as policy enforcement point. An access control policy
system must transform all active policies into configurations of the
SNMP agent's User Based Security Model (USM) and the View-based
Access Control Model (VACM).
The mechanisms of USM allow an access control policy system to
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enforce MIDCOM agent authentication rules and general access control
of MIDCOM agents to middlebox control.
The mechanisms of VACM can be used to enforce access control of
authenticated agents to MIDCOM policy rules based on the concept of
ownership. For example, an access control policy can specify that
MIDCOM policy rules owned by user A, cannot be accessed at all by
user B, can be read by user C, and can be read and modified by user
D.
Further access control policies can control access to concrete
middlebox resources. These are enforces, when a MIDCOM request is
processed. For example an authenticated MIDCOM agent may be
authorized to request new MIDCOM policies to be established, but only
for certain IP address ranges. The enforcement of this kind of
policies cannot be realized by using available SNMP mechanisms, but
needs to be performed by the individual MIB module implementation.
5. Structure of the MIB module
This section presents the structure of the MIB module that is
specified in Section 5. The MIB is structured strictly according to
the MIDCOM semantics described in [RFCXXXX].
The MIDCOM semantics definition is structured into three major
sections: session control, policy rule control and policy rule group
control. Accordingly, the MIDCOM MIB module contains three tables:
the midcomSessionTable, the midcomRuleTable and the midcomGroupTable.
Additionally, a set of scalar managed objects describe the middlebox
capabilities.
5.1. midcomCapabilities
Information on middlebox capabilites is provided by the
midcomCapabilities group of managed objects. The following objects
are defined:
o midcomCapabFirewall
This is a boolean object indicating whether or not the middlebox
acts as firewall.
o midcomCapabNat
This is a boolean object indicating whether or not the middlebox
acts as network address translator.
o midcomCapabPortTranslation
This is a boolean object indicating whether or not the middlebox
is capable of performing port translation.
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o midcomCapabProtocolTranslation
This is a boolean object indicating whether or not the middlebox
is capable of performing protocol translation.
o midcomCapabTwiceNat
This is a boolean object indicating whether or not the middlebox
acts twice-NAT.
o midcomCapabInsideIpVersions
This objects lists the IP versions available at the inside of
the middlebox.
o midcomCapabOutsideIpVersions
This objects lists the IP versions available at the outside of
the middlebox.
o midcomCapabInsideWildcards
This is a boolean object indicating whether or not the middlebox
is capable of performing IP address wildcarding at the inside.
o midcomCapabOutsideWildcards
This is a boolean object indicating whether or not the middlebox
is capable of performing IP address wildcarding at the outside.
o midcomCapabPortWildcards
This is a boolean object indicating whether or not the middlebox
is capable of performing wilcarding of port numbers.
o midcomCapabPersistentRules
This is a boolean object indicating whether or not the middlebox
is capable of storing policy rules persistently.
o midcomCapabMaxLifetime
This object indicates the maximum lifetime that this middlebox
allows policy rules to have.
5.2. midcomSessionTable
The midcomSessionTable models MIDCOM sessions. For opening a
session, a MIDCOM agent has to create a row in this table.
Without an entry in the midcomSessionTable, no policy rules can be
established. New entries in the midcomRuleTable are created by
writing to the object called midcomSessionCreateRule in the
midcomSessionTable. The MIDCOM agent can specify the group
membership and the default rule storage time of created enties in the
midcomRuleTable by setting the corresponding objects in the
midcomSessionTable.
The midcomSessionTable is indexed by the SNMP user name of the
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authenticated MIDCOM agent.
In particular, the midcomSessionTable contains the following objects:
o midcomSessionOwner
This string indicated the user that created and owns the
session. It is the index of this table. All policy rules (and
policy rule groups) have the same owner as the corresponding
entry in the midcomSessionTable from which they were created.
o midcomSessionIndex
An index that serves for distiguishing different sessions of the
same midcomSessionOwner.
o midcomSessionRuleGroupIndex
The group to which policy rules created from the same session
should be a member of.
o midcomSessionRuleStorageTime
The default time policy rules created from the same session
should be stored in the midcomPolicyTable after they are
terminated.
o midcomSessionRuleIndexNext
An object that can be read for obtaining an object identifier
pointing to a so far not exsiting entry in the midcomRuleTable.
o midcomSessionCreateRule
Writing a value read from midcomSessionRuleIndexNext to this
object creates a new entry in the midcomRuleTable.
o midcomSessionStorageType
This object indicates whether or not the session is volatile,
non-volatile, or permanent. Depending on the MIDCOM MIB
implementation this object may be writable.
o midcomSessionRowStatus
Writing to this object creates or deletes a row in the
midcomSessionTable, i.e. it opens or terminates a session,
respectively.
5.3. midcomRuleTable
The midcomRuleTable contains information about policy rules including
policy rules to be established, policy rules for which establishing
failed, establishe policy rules and terminated policy rules.
Entries in this table are indexed by the combination of a
midcomSessioOwner, a midcomGroupIndex and a midcomRuleIndex. The
midcomSessionOwner is the owner of the session from which the entry
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was created, the midcomGroupIndex is the index of the group of which
the policy rule is a member.
Entries in this table can only be created by writing to
midcomSessionCreateRule in the midcomSessionTable. Entries are
removed, when their midcomRuleLifetime and midcomRuleStorageTime are
timed out by counting down to 0. A MIDCOM agent can explicitly
remove an entry by setting midcomRuleLifetime and
midcomRuleStorageTime to 0.
The table contains the following objects:
o midcomRuleIndex
The index of this entry must be unique in combination with the
midcomSessionOwner and the midcomGroupindex of the entry.
o midcomRuleAdminStatus
For establishing a new policy rule, a set of objects in this
entry needs to be written first. These objects are the request
parameters. Then, by writing either reserved(1) or enabled(2)
to this object, the MIDCOM MIB implementation starts processing
the parameters and tries to establish the specified policy rule.
o midcomRuleOperStatus
This read-only object indicates the current status of the entry.
The entry may have an initializing state, it may have a
transient state while processing requests, it may have an error
state after a request was rejected, it may have a state where a
policy rule is established, or it may have a terminated state.
o midcomRuleStorageType
This object indicates whether or not the policy rule is stored
as volatile, non-volatile, or permanent. Depending on the
MIDCOM MIB implementation this object may be writable.
o midcomRuleStorageTime
This object indicates how long the entry will still exist after
entering an error state or a termiantion state.
o midcomRuleError
This object is a string indicating the reason for entering an
error state.
o midcomRuleNatService
This object indicates which kind of NAT service is requested or
established, respectively. Possible NAT services are
traditional NAT and twice-NAT.
o midcomRuleTransportProtocol
This object indicates a transport protocol for which a policy
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reserve rule or policy enable rule was requested or established,
respectively.
o midcomRulePortRange
This object indicates a port ramnge for which a policy reserve
rule or policy enable rule was requested or established,
respectively.
o midcomRulePortParity
This object indicates a port parity for which a policy reserve
rule or policy enable rule was requested or established,
respectively.
o midcomRuleFlowDirection
This object indicates a flow direction for which a policy enable
rule was requested or established, respectively.
o midcomRuleLifetime
This object indicates the reamining lifetime of an established
policy rule. The MIDCOM agent can change the remaining lifetime
by writing to it.
Beyond the listed objects, the table contains 14 further objects
describing address parameters. They include the IP version, IP
address and port number for the internal address (A0), inside address
(A1), outside address (A2) and external address (A3) and they include
interface numbers for A1 and A2. These objects serve as parameters
specifying a request or an established policy, respectively.
5.4. midcomGroupTable
The midcomGroupTable has an entry per existing polcy rule group.
Entries of this table are created automatically when creating entries
in the midcomRuleTable. Entries are automatically removed from this
table, when the last member entry is removed from the
midcomRuleTable. Entries cannot be created or removed explicitly by
the MIDCOM agent.
Entries are indexed by the midcomSessionOwner of the session from
which the policies belonging to the group where created.
an entry of the table contains the following objects:
o midcomGroupIndex
The index of this entry must be unique in combination with the
midcomSessionOwner of the entry.
o midcomGroupLifetime
This object indicates the maximum of the reamining lifetimes of
all established policy rules that are members of the group. The
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MIDCOM agent can change the remaining lifetime of all member
policies by writing to this object.
5.5. midcomEvent
To be done: description of midcomSessionTermination,
midcomRuleEvent, midcomGroupEvent.
6. Definitions
MIDCOM-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE,
NOTIFICATION-TYPE, Unsigned32, mib-2
FROM SNMPv2-SMI -- RFC2578
TruthValue, StorageType, RowStatus,
TimeInterval
FROM SNMPv2-TC -- RFC2579
MODULE-COMPLIANCE, OBJECT-GROUP
FROM SNMPv2-CONF -- RFC2580
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB -- RFC3411
InetAddressType, InetAddress,
InetPortNumber
FROM INET-ADDRESS-MIB -- RFC 3291
InterfaceIndex
FROM IF-MIB; -- RFC2863
midcomMIB MODULE-IDENTITY
LAST-UPDATED "200310070333Z" -- October 07, 2003
ORGANIZATION "IETF Middlebox Communication Working Group"
CONTACT-INFO
"WG charter:
http://www.ietf.org/html.charters/midcom-charter.html
Mailing Lists:
General Discussion: midcom@ietf.org
To Subscribe: midcom-request@ietf.org
In Body: subscribe your_email_address
Editor:
Martin Stiemerling
NEC Europe Ltd.
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Network Laboratories
Kurfuersten-Anlage 36
69221 Heidelberg
Germany
Tel: +49 6221 90511-13
Email: stiemerling@ccrle.nec.de"
DESCRIPTION
"This MIB module defines a set of basic objects for
configuring middleboxes, such as firewalls and network
address translators, in order to enable communication
across these devices.
There are four groups of managed objects defined
by this MIB module:
- objects describing middlebox capabilities
in the midcomCapabilities group,
- objects modeling MIDCOM sessions in the
midcomSessionTable
- objects modeling MIDCOM policy rules in the
midcomRuleTable
- objects modeling MIDCOM polcy rule groups in the
midcomGroupTable
Copyright (C) The Internet Society (2003). This version
of this MIB module is part of RFC yyyy; see the RFC
itself for full legal notices."
-- RFC Ed.: replace yyyy with actual RFC number & remove this notice
REVISION "200310070333Z" -- October 07, 2003
DESCRIPTION "Initial version, published as RFC yyyy."
-- RFC Ed.: replace yyyy with actual RFC number & remove this notice
::= { mib-2 4444 }
-- 4444 to be assigned by IANA.
--
-- main components of this MIB module
--
midcomObjects OBJECT IDENTIFIER ::= { midcomMIB 1 }
midcomNotifications OBJECT IDENTIFIER ::= { midcomMIB 2 }
midcomConformance OBJECT IDENTIFIER ::= { midcomMIB 3 }
--
-- Capabilities group
--
-- The MIDCOM capabilities group contains a set of managed
-- objects describing the capabilities of the middlebox.
-- All objects in this group have MAX-ACCESS read-only.
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--
midcomCapabilities OBJECT IDENTIFIER ::= { midcomObjects 1 }
midcomCapabFirewall OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node acts as firewall. Otherwise, it returns false(2)."
::= { midcomCapabilities 1 }
midcomCapabNat OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node acts as network address tranlator. Otherwise, it
returns false(2)."
::= { midcomCapabilities 2 }
midcomCapabPortTranslation OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node acts as network address translator and supports port
transaltion. Otherwise, it returns false(2)."
::= { midcomCapabilities 3 }
midcomCapabProtocolTranslation OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node acts as network address translator and supports protocol
transaltion. Otherwise, it returns false(2)."
::= { midcomCapabilities 4 }
midcomCapabTwiceNat OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node acts as twice network address translator. Otherwise,
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it returns false(2)."
::= { midcomCapabilities 5 }
midcomCapabInsideIpVersions OBJECT-TYPE
SYNTAX INTEGER {
ipv4(1),
ipv6(2),
both(3)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns ipv4(1) if the managed
node supports IPv4 only at the inside. It returns ipv6(2)
if it supports IPv6 only at the inside. Otherwise, if it
supports voth IP version, it returns both(3)."
::= { midcomCapabilities 6 }
midcomCapabOutsideIpVersions OBJECT-TYPE
SYNTAX INTEGER {
ipv4(1),
ipv6(2),
both(3)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns ipv4(1) if the managed
node supports IPv4 only at the outside. It returns ipv6(2)
if it supports IPv6 only at the outside. Otherwise, if it
supports voth IP version, it returns both(3)."
::= { midcomCapabilities 7 }
midcomCapabInsideWildcards OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node supports IP address wildcarding at the inde. Otherwise,
it returns false(2)."
::= { midcomCapabilities 8 }
midcomCapabOutsideWildcards OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node supports IP address wildcarding at the outde. Otherwise,
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it returns false(2)."
::= { midcomCapabilities 9 }
midcomCapabPortWildcards OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node supports port wildcarding. Otherwise, it returns
false(2)."
::= { midcomCapabilities 10 }
midcomCapabPersistentRules OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns true(1) if the managed
node can store policy rules persistently. Otherwise, it
returns false(2)."
::= { midcomCapabilities 11 }
midcomCapabMaxLifetime OBJECT-TYPE
SYNTAX TimeInterval
UNITS "centi-seconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns the maximum lifetime
in centi-seconds, that this middlebox allows policy rules
to have."
::= { midcomCapabilities 12 }
--
-- Session group
--
-- The midcomSessionTable models MIDCOM sessions.
-- MIDCOM agents ( = SNMP managers ) that want to
-- read, create or modify entries in the midcomRuleTable
-- or midcomGroupTable need to have an entry in this table.
--
-- The table contains objects identify a destination for
-- notifications to be sent to the MIDCOM agent.
-- Also it serves for creating new rows in the
-- midcomRuleTable.
--
midcomSession OBJECT IDENTIFIER ::= { midcomObjects 2 }
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midcomSessionIndexNext OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns an unused session
index for the USM user that issued the read-request.
The returned value can be used for creating a new entry
in the midcomSessionTable.
A value retuned when reading this object is not returned
again on subsequent read-requests as long as possible.
This ensures that two SNMP managers authenticated as the
same USM user can independently create sessions without
facing race conditions."
::= { midcomSession 1 }
midcomSessionTable OBJECT-TYPE
SYNTAX SEQUENCE OF MidcomSessionEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table lists open MIDCOM sessions.
The midcomSessionTable models MIDCOM sessions.
MIDCOM agents ( = SNMP managers ) that want to
read, create or modify entries in the midcomRuleTable
or midcomGroupTable need to have an entry in this
table.
The table contains objects identify a destination for
notifications to be sent to the MIDCOM agent.
Also, it serves for creating new rows in the
midcomRuleTable.
The midcomSessionTable is indexed by its owner
identified as USM user, and by a session index
that allows distinguishing multiple sessions of
the same USM users."
::= { midcomSession 2 }
midcomSessionEntry OBJECT-TYPE
SYNTAX MidcomSessionEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry describing a particular MIDCOM session."
INDEX { midcomSessionOwner, midcomSessionIndex }
::= { midcomSessionTable 1 }
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MidcomSessionEntry ::= SEQUENCE {
midcomSessionOwner SnmpAdminString,
midcomSessionIndex Unsigned32,
midcomSessionRuleGroupIndex Unsigned32,
midcomSessionRuleStorageTime TimeInterval,
midcomSessionRuleIndexNext OBJECT IDENTIFIER,
midcomSessionCreateRule OBJECT IDENTIFIER,
midcomSessionStorageType StorageType,
midcomSessionRowStatus RowStatus
}
midcomSessionOwner OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE (0..32))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The manager ( = MIDCOM agent ) who owns this row
in the midcomSessionTable.
Every policy rule created from a particular
entry in the midcomSessionTable (i.e. entries
in the midcomRuleTable) will be owned by the same
midcomSessionOwner used to index the entry in the
midcomSessionTable."
::= { midcomSessionEntry 1 }
midcomSessionIndex OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This object allows distinguishing multiple concurrent
sessions of the same USM user. Its value needs to be
unique per USM user."
::= { midcomSessionEntry 2 }
midcomSessionRuleGroupIndex OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This object determines the index of the MIDCOM policy
rule group of which policy rules becomes a member when
they are created by writing to midcomSessionCreateRule.
The value 0 is not a valid group index. When this object
has a value of 0, then a new group is created for each
new policy rule generated by writing to
midcomSessionCreateRule."
DEFVAL { 0 }
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::= { midcomSessionEntry 3 }
midcomSessionRuleStorageTime OBJECT-TYPE
SYNTAX TimeInterval
UNITS "centi-seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This object indicates the default maximum amount of time
information on a policy rule is kept as entry in the
mibRuleTable after the entry reaches an error state or
after the policy rule is terminated. The value of this
object is used to initialize the midcomRuleStorageTime
when a new entry in the midcomRuleTable is created.
Changing the value of an midcomSessionRuleStorageTime
instance does not affect any entry of the midcomRuleTable
created previously."
DEFVAL { 60000 }
::= { midcomSessionEntry 4 }
midcomSessionRuleIndexNext OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"When retrieved, this object returns an object identifier
pointing to a not yet existing row in the midcomRuleTable.
The first index of the object identifier is the value of
the midcomSessionOwner object of the actual entry in the
midcomSessionTable.
The second index is the value of the
midcomSessionGroupIndex object of the actual entry in the
midcomSessionTable, if this value is not 0. If the value
is zero, then the second index is the midcomGroupIndex of
a not yet existing entry in the midcomGroupTable.
The third index is a so far unused policy rule index for
members of the group identified by the second index.
The returned value can be used for creating a new entry
in the midcomRuleTable by writing it to
midcomSessionCreateRule."
::= { midcomSessionEntry 5 }
midcomSessionCreateRule OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-write
STATUS current
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DESCRIPTION
"Writing to this object potentially creates a new entry in
the midcomRuleTable. A value written to this object should
be an object identifier pointing to a so far not existing
entry in the midcomRuleTable. Also it should use the
value of the midcomSessionOwner iobject of the acual
entry in the midcomSessionTable as first index. If one
of these constraints is not given, then the operation
will result in an inconsistentValue error.
Also, the value must use the midcomSessionOwner of
the actual entry in the midcomSessionTable as first index.
Valid values for writing to this object can be obtained
by reading the midcomSessionRuleIndexNext object.
If the value is valid, then the MIDCOM MIB implementation
creates a new entry in the midcomRuleTable using the
value."
::= { midcomSessionEntry 6 }
midcomSessionStorageType OBJECT-TYPE
SYNTAX StorageType
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"to be done"
DEFVAL { volatile }
::= { midcomSessionEntry 7 }
midcomSessionRowStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Needed for creating sessions. Detailed description
to be done."
::= { midcomSessionEntry 8 }
--
-- Policy rule group
--
-- The midcomRuleTable lists all current policy rules
-- including policy reserve rules and policy enable rules.
--
midcomRuleTable OBJECT-TYPE
SYNTAX SEQUENCE OF MidcomRuleEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
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"This table lists all current policy rules.
It is indexed by the midcomSessionOwner, the
midcomGroupIndex and the midcomRuleIndex.
This implies that a rule is member of exactly
one group and that group membership cannot
be changed.
Entries in this table are created implicitly
by writing to the midcomSessionTable. Entries
are deleted by writing to midcomGroupLifetime
or midcomRuleLifetime."
::= { midcomObjects 3 }
midcomRuleEntry OBJECT-TYPE
SYNTAX MidcomRuleEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry describing a particular MIDCOM policy rule.
It must be unque in combination with the
midcomSessionOwner, the midcomGroupIndex, and the
midcomRuleIndex of this entry."
INDEX { midcomSessionOwner, midcomGroupIndex, midcomRuleIndex }
::= { midcomRuleTable 1 }
MidcomRuleEntry ::= SEQUENCE {
midcomRuleIndex Unsigned32,
midcomRuleAdminStatus INTEGER,
midcomRuleOperStatus INTEGER,
midcomRuleStorageType StorageType,
midcomRuleStorageTime TimeInterval,
midcomRuleError SnmpAdminString,
midcomRuleNatService INTEGER,
midcomRuleInternalIpVersion InetAddressType,
midcomRuleInternalIpAddr InetAddress,
midcomRuleInternalPort InetPortNumber,
midcomRuleInsideIpVersion InetAddressType,
midcomRuleInsideIpAddr InetAddress,
midcomRuleInsidePort InetPortNumber,
midcomRuleInsideInterface InterfaceIndex,
midcomRuleOutsideIpVersion InetAddressType,
midcomRuleOutsideIpAddr InetAddress,
midcomRuleOutsidePort InetPortNumber,
midcomRuleOutsideInterface InterfaceIndex,
midcomRuleExternalIpVersion InetAddressType,
midcomRuleExternalIpAddr InetAddress,
midcomRuleExternalPort InetPortNumber,
midcomRuleTransportProtocol Unsigned32, -- defintion?
midcomRulePortRange Unsigned32,
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midcomRulePortParity INTEGER,
midcomRuleFlowDirection INTEGER,
midcomRuleLifetime TimeInterval
}
midcomRuleIndex OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The value of this object must be unique in
combination with the values of
midcomSessionOwner and midcomGroupIndex.
The value of this index is chosen by the MIDCOM
MIB implementation when a new entry in this row
is created."
::= { midcomRuleEntry 3 }
midcomRuleAdminStatus OBJECT-TYPE
SYNTAX INTEGER {
reserved(1),
enabled(2)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value of this object indicates the desired status of
the policy rule. See the definition of midcomRuleOperStatus
for a description of the values.
When the midcomRuleAdminStatus object is set, then the
MIDCOM MIB implementation will try to read the respective
relvant objects of the entry and try to achieve the
corresponding midcomRuleOperStatus.
Depending on whether the midcomRuleAdminStatus is set to
reserved(1) or enabled(2) several entries in MidcomRuleEntry
must be set.
In the reserved(1) case these entries must be set for
a request:
- midcomRuleNatService
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideInterface
- midcomRuleOutsideInterface
- midcomRuleExternalIpVersion
- midcomRuleTransportProtocol
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- midcomRulePortRange
- midcomRulePortParity
In the enabled(2) case these entries must be set for a
request:
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideInterface
- midcomRuleOutsideInterface
- midcomRuleExternalIpVersion
- midcomRuleExternalIpAddr
- midcomRuleExternalPort
- midcomRuleTransportProtocol
- midcomRulePortRange
- midcomRulePortParity
- midcomRuleFlowDirection
When retrieved, the object returns the last set value. If
no value has been set, it returns one of the two possible
values."
::= { midcomRuleEntry 4 }
midcomRuleOperStatus OBJECT-TYPE
SYNTAX INTEGER {
newEntry(1),
setting(2),
checkingRequest(3),
incorrectRequest(4),
processingRequest(5),
requestRejected(6),
reserved(7),
checkingTransitRequest(8),
processingTransitRequest(9),
enabled(10),
timedOut(11),
terminatedOnRequest(12),
terminated(13),
genericError(14)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The actual status of the policy rule. The
midcomRuleOperStatus object may have the following values:
- newEntry(1) indicates that the entry in the
midcomRuleTable was created, but not modified yet.
Such an entry needs to be filled with values specifying
a request first.
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- setting(2) indicates that the entry has been already
modified after generating it, but no request was made
yet.
- checkingRequest(3) indicates that midcomRuleAdminStatus
has recently been set and that the MIDCOM MIB
implementation is currently checking the parameters of
the request.
- incorrectRequest(4) indicates that checking a request
resulted in detecting an incorrect value in one of the
objects containing request parameters. The failure
reason is indicated by the value of midcomRuleError.
- processingRequest(5) indicates that
midcomRuleAdminStatus has recently been set and that
the MIDCOM MIB implementation is currently processing
the request and trying to configure the middlebox
accordingly.
- requestRejected(6) indicates that a request to establish
a policy rule specified by the entry was rejected. The
reason of rejection is indicated by the value of
midcomRuleError.
- reserved(7) indicates that the entry describes an
established policy reserve rule.
These values of MidcomRuleEntry can be retrieved
for a reserved policy rule:
- midcomRuleNatService
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideIpVersion
- midcomRuleInsideIpAddr
- midcomRuleInsidePort
- midcomRuleInsideInterface
- midcomRuleOutsideIpVersion
- midcomRuleOutsideIpAddr
- midcomRuleOutsidePort
- midcomRuleExternalIpVersion
- midcomRuleTransportProtocol
- midcomRulePortRange
- midcomRulePortParity
- midcomRuleLifetime
- checkingTransitRequest(8) indicates that after a policy
reserve rule was established, midcomRuleAdminStatus has
recently been set to enabled(10) and that the MIDCOM MIB
implementation is currently checking the parameters of
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the request.
- processingTransitRequest(9) indicates that after a policy
reserve rule was established, midcomRuleAdminStatus has
recently been set to enabled(10) and that the MIDCOM MIB
implementation is currently processing the request and
trying to configure the middlebox accordingly.
- enabled(10) indicates that the entry describes an
established policy enable rule.
These values of MidcomRuleEntry can be retrieved
for an enabled policy rule
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideIpVersion
- midcomRuleInsideIpAddr
- midcomRuleInsidePort
- midcomRuleInsideInterface
- midcomRuleOutsideIpVersion
- midcomRuleOutsideIpAddr
- midcomRuleOutsidePort
- midcomRuleOutsideInterface
- midcomRuleExternalIpVersion
- midcomRuleExternalIpAddr
- midcomRuleExternalPort
- midcomRuleTransportProtocol
- midcomRulePortRange
- midcomRulePortParity
- midcomRuleFlowDirection
- midcomRuleLifetime
- timedOut(11) indicates that the lifetime of a previously
established policy rule is expired and that the policy
rule is terminated for this reason.
- terminatedOnRequest(12) indicates that a previously
established policy rule was terminated by an SNMP
manager setting the midcomRuleLifetime to 0 or
setting midcomGroupLifetime to 0.
- terminated(13) indicates that a previously established
policy rule was terminated by the MIDCOM MIB
implementation for another reason than lifetime
expiration or an explicit request from an SNMP
manager.
- genericError(14) indicates that the policy rule
specified by the entry is not established due to
an error condition not listed above.
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The states timedOut(11), terminatedOnRequest(12) and
terminated(13) are referred to as termination states.
The states incorrectRequest(4), requestRejected(6)
and genericError(14) are referred to as error states.
The checkingRequest(3), processingRequest(4),
checkingTransitRequest(8) and checkingTransitRequest(9)
states are transient states which will either lead to one
of the error states or the reserved(7) state or the
enabled(10) states."
DEFVAL { newEntry }
::= { midcomRuleEntry 5 }
midcomRuleStorageType OBJECT-TYPE
SYNTAX StorageType
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This object defines whether this row and the policy
rule controlled by this row are kept in volatile
storage and lost upon reboot or if this row is
backed up by non-volatile or permanent storage.
Attempts to set this object to permanent will always
fail with an inconsistentValue error.
If midcomRuleStorageType has the value permanent(4),
then all objects whose MAX-ACCESS value is read-write
must be read-only."
DEFVAL { volatile }
::= { midcomRuleEntry 6 }
midcomRuleStorageTime OBJECT-TYPE
SYNTAX TimeInterval
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value of this object specifies how long this row
can exist in the midcomRuleTable after the
midcomRuleOperState switched to a termination state or
to an error state. This object returns the remaining
time that the row may exist before it is aged out.
The object is initialized with the value of the
associated midcomSessionStorageTime object.
After expiration or termination of the context, the value
of this object ticks backwards. The entry in the
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midcomRuleTable is destroyed when the value reaches 0.
The value of this object may be set in order to increase
or reduce the remaining time that the row may exist.
Setting the value to 0 will destroy this entry as soon as
the midcomRuleOperState switched to a termination state
or to an error state.
Note that there is no guarantee that the row is stored as
long as this object indicates. At any time, the SNMP
agent may decide to remove a row describing a terminated
policy rule before the storage time of the corresponding
row in the midcomRuleTable reaches the value of 0. In
this case the information stored in this row is not
anymore available."
::= { midcomRuleEntry 7 }
midcomRuleError OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object contains a descriptive error message if
the transition into the operational status reserved(7)
or enabled(10) failed. Implementations must reset the
error message to a zero-length string when a new
attempt to change the policy rule status to reserved(7)
or enabled(10) is started."
DEFVAL { ''H }
::= { midcomRuleEntry 8 }
midcomRuleNatService OBJECT-TYPE
SYNTAX INTEGER {
traditionalNat(1),
twiceNat(2)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The requested NAT service of the middlebox. Some NATs may
have dual characters, like providing traditional and
twice NAT service at the same time for different NAT bindings.
This parameter determines the behaviour for this NAT binding.
A firewall only middlebox ignores this parameter.
The midcomRuleService is only available for policy reserve
rules, indicated by midcomRuleAdminStatus set to reserved(1)."
::= { midcomRuleEntry 9 }
midcomRuleInternalIpVersion OBJECT-TYPE
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SYNTAX InetAddressType
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"IP version at the inside of the middlebox."
::= { midcomRuleEntry 10 }
midcomRuleInternalIpAddr OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The internal IP address at the middlebox."
::= { midcomRuleEntry 11 }
midcomRuleInternalPort OBJECT-TYPE
SYNTAX InetPortNumber
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The internal port at the middlebox."
::= { midcomRuleEntry 12 }
midcomRuleInsideIpVersion OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"IP version at the inside of the middlebox.
The midcomRuleInsideIpVersion is set by the SNMP agent
to the IP address type, when the middlebox is twice-NAT
and twice-NAT service is requested.
The midcomRuleInsideIpVersion must be set to unknown(0) when
the NAT does not assign an inside IP address. Firewalls
always return unkown(0), since no inside IP address is assigned."
::= { midcomRuleEntry 13 }
midcomRuleInsideIpAddr OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The inside IP address at the middlebox.
The midcomRuleInsideIpAddr is set by the SNMP agent
to the IP address, when the middlebox is twice-NAT
and twice-NAT service is requested."
::= { midcomRuleEntry 14 }
midcomRuleInsidePort OBJECT-TYPE
SYNTAX InetPortNumber
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MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The inside port at the middlebox.
The midcomRuleInsideIpPort is set by the SNMP agent
to the IP port number, when the middlebox is twice-NAT
and twice-NAT service is requested."
::= { midcomRuleEntry 15 }
midcomRuleInsideInterface OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The interface at the inside of the middlebox."
::= { midcomRuleEntry 16 }
midcomRuleOutsideIpVersion OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"IP version at the outside of the middlebox.
The midcomRuleOutsideIpVersion is set by the SNMP agent
to the IP address type.
Firewalls always return unkown(0), since no inside IP address
is assigned."
::= { midcomRuleEntry 17 }
midcomRuleOutsideIpAddr OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The outside IP address at the middlebox.
The midcomRuleOutsideIpAddr is set by the SNMP agent
to the IP address."
::= { midcomRuleEntry 18 }
midcomRuleOutsidePort OBJECT-TYPE
SYNTAX InetPortNumber
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The outside port at the middlebox.
The midcomRuleOutsideIpPort is set by the SNMP agent
to the IP address type."
::= { midcomRuleEntry 19 }
midcomRuleOutsideInterface OBJECT-TYPE
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SYNTAX InterfaceIndex
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The interface at the outside of the middlebox."
::= { midcomRuleEntry 20 }
midcomRuleExternalIpVersion OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"IP version at the external of the middlebox."
::= { midcomRuleEntry 21 }
midcomRuleExternalIpAddr OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The external IP address at the middlebox.
The midcomExternalIpAddr is only available for policy
enable rule requests, indicated by midcomRuleAdminStatus set
to enabled(2)."
::= { midcomRuleEntry 22 }
midcomRuleExternalPort OBJECT-TYPE
SYNTAX InetPortNumber
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The external port at the middlebox.
The midcomExternalPort is only available for policy
enable rule requests, indicated by midcomRuleAdminStatus set
to enabled(2)."
::= { midcomRuleEntry 23 }
midcomRuleTransportProtocol OBJECT-TYPE
SYNTAX Unsigned32 (0..255)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The transport protocol."
::= { midcomRuleEntry 24 }
midcomRulePortRange OBJECT-TYPE
SYNTAX Unsigned32 (1..65535)
MAX-ACCESS read-write
STATUS current
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DESCRIPTION
"The port range parameter specifies a number of
consecutive port numbers. Its value is a positive integer.
Together with the port number parameter this parameter defines
a set of consecutive port numbers starting with the port number
specified by the port number parameter as the lowest port
number and having as many elements as specified by the port
range parameter. A value of one specifies just a single port
number."
::= { midcomRuleEntry 25 }
midcomRulePortParity OBJECT-TYPE
SYNTAX INTEGER {
same(1), -- available for PER only
any(2), -- available for PER and PRR
odd(3), -- available for PRR only
even(4) -- available for PRR only
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The port parity parameter is differently used in the
context of policy reserve rules (PRR, midcomRuleAdminStatus
set to reserved(1)) and policy enable rules (PER,
midcomRuleAdminStaus set to enabled(2)). In the context
of a PRR, the value of the parameter may be 'odd',
'even', or 'any'. It specifies the parity of the first
(lowest) reserved port number.
In the context of a PER, the port parity parameter
indicates to the middlebox, whether or not port numbers
allocated at the middlebox should have the same parity
as the corresponding internal or external port numbers,
respectively. In this context, the parameter has either
the value 'same' or 'any'. If it has the value 'same',
then the parity of the port number of A0 must be the
same as the parity of the port number of A2, and the
parity of the port number of A1 must be the same as the
parity of the port number of A3. If the port parity
parameter has the value 'any', then there are no constraints
on the parity of any port number."
::= { midcomRuleEntry 26}
midcomRuleFlowDirection OBJECT-TYPE
SYNTAX INTEGER {
inbound(1),
outbound(2),
bidirectional(3)
}
MAX-ACCESS read-write
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STATUS current
DESCRIPTION
"This parameter specifies the direction of enabled communication,
either 'inbound', 'outbound', or 'bi-directional'.
The midcomRuleFlowDirection is only available for policy
enable rule requests, indicated by midcomRuleAdminStatus set
to enabled(2)."
::= { midcomRuleEntry 27 }
midcomRuleLifetime OBJECT-TYPE
SYNTAX TimeInterval
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"When retrieved, this object delivers the the reamining
lifetime in centi-seconds of this policy rule.
Successfully writing to this object modifies the
lifetime of the policy rule. Successfully
writing a value of 0 terminates the policy rule.
Note that after a policy rule is terminated,
still the entry will exist as long as indicated by
the value of midcomRuleStorageTime.
Writing to this object is processed by the SNMP agent
according to the processing of a Policy Rule Lifetime Change
(RLC) request as specified in RFC XXXX. Therefore,
SNMP set requests to this object might be rejected or
the value of the object after an accepted set operation
may be different from the value that was contained in
the SNMP set request."
::= { midcomRuleEntry 28 }
--
-- Policy rule group group
--
-- The midcomGroupTable lists all current policy rule groups.
--
midcomGroupTable OBJECT-TYPE
SYNTAX SEQUENCE OF MidcomGroupEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table lists all current policy rule groups.
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Entries in this table are created implicitely when
entries in the midcomRuleTable are created.
Like the midcomSessionTable and the midcomRuleTable,
this table is indexed by an owner and an index that
is unique per owner.
The table serves for listing the existing groups and
their remaining lifetimes and for changing lifetimes
of groups and implicitly of all group members.
Groups and all their member policy rules can be
deleted by setting midcomGroupLifetime to 0."
::= { midcomObjects 4 }
midcomGroupEntry OBJECT-TYPE
SYNTAX MidcomGroupEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry describing a particular MIDCOM session."
INDEX { midcomSessionOwner, midcomGroupIndex }
::= { midcomGroupTable 1 }
MidcomGroupEntry ::= SEQUENCE {
midcomGroupIndex Unsigned32,
midcomGroupLifetime TimeInterval
}
midcomGroupIndex OBJECT-TYPE
SYNTAX Unsigned32 (1..4294967295)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The index of this group for the midcomSessionOwner.
A group is identified by the combination of
midcomSessionOwner and midcomGroupIndex.
The value of this index must be unique per
midcomSessionOwner."
::= { midcomGroupEntry 2 }
midcomGroupLifetime OBJECT-TYPE
SYNTAX TimeInterval
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"When retrieved, this object delivers the the maximum
lifetime in centi-seconds of all member rules of this
group, i.e. of all rows in the midcomRuleTable that
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have the same values for midcomSessionOwner and
midcomGroupIndex.
Successfully writing to this object modifies the
lifetime of all member policies. Successfully
writing a value of 0 deletes the group and all its
member rules.
Note that after a group is conceptually deleted,
still the corresponding entry in the midcomGroupTable
will exist as long as terminated member policy rules
are stored as entries in the midcomRuleTable.
Writing to this object is processed by the SNMP agent
according to the processing of a Group Lifetime Change
(GLC) request as specified in RFC XXXX. Therefore,
SNMP set requests to this object might be rejected or
the value of the object after an accepted set operation
may be different from the value that was contained in
the SNMP set request."
::= { midcomGroupEntry 3 }
--
-- Notifications. The definition of midcomEvent makes notification
-- registrations reversible (see STD 58, RFC 2578, Section 8.5).
--
midcomEvent OBJECT IDENTIFIER ::= { midcomNotifications 0 }
midcomSessionTermination NOTIFICATION-TYPE
STATUS current
DESCRIPTION
"This notification can be generated for indicating
that a session is terminated by the middlebox."
::= { midcomEvent 1 }
midcomRuleEvent NOTIFICATION-TYPE
OBJECTS { midcomRuleLifetime }
STATUS current
DESCRIPTION
"This notification can be generated for indicating the
change of a policy rule's lifetime."
::= { midcomEvent 2 }
midcomGroupEvent NOTIFICATION-TYPE
OBJECTS { midcomGroupLifetime }
STATUS current
DESCRIPTION
"This notification can be generated for indicating the
change of a policy rule group's lifetime."
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::= { midcomEvent 3 }
--
-- Conformance information
--
midcomCompliances OBJECT IDENTIFIER ::= { midcomConformance 1 }
midcomGroups OBJECT IDENTIFIER ::= { midcomConformance 2 }
--
-- compliance statements
--
-- This is the MIDCOM compliance definition ...
--
midcomCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for SNMP entities that
implement the MIDCOM MIB.
Note that compliance with this compliance
statement requires compliance with the
ifCompliance3 MODULE-COMPLIANCE statement of the
IF-MIB [RFC2863]."
MODULE -- this module
MANDATORY-GROUPS {
midcomCapabilitiesGroup,
midcomSessionGroup,
midcomRuleGroup,
midcomNotificationsGroup
}
GROUP midcomGroupGroup
DESCRIPTION
"A compliant implementation does not have to implement
the midcomGroupGroup."
OBJECT midcomRuleInsideInterface
MIN-ACCESS not-accessible
DESCRIPTION
"A compliant implementation does not have to implement
object midcomRuleInsideInterface."
OBJECT midcomRuleOutsideInterface
MIN-ACCESS not-accessible
DESCRIPTION
"A compliant implementation does not have to implement
object midcomRuleOutsideInterface."
::= { midcomCompliances 1 }
midcomCapabilitiesGroup OBJECT-GROUP
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OBJECTS {
midcomCapabFirewall,
midcomCapabNat,
midcomCapabPortTranslation,
midcomCapabProtocolTranslation,
midcomCapabTwiceNat,
midcomCapabInsideIpVersions,
midcomCapabOutsideIpVersions,
midcomCapabInsideWildcards,
midcomCapabOutsideWildcards,
midcomCapabPortWildcards,
midcomCapabPersistentRules,
midcomCapabMaxLifetime
}
STATUS current
DESCRIPTION
"A collection of objects providing information about
the capabilities of a middlebox."
::= { midcomGroups 1 }
midcomSessionGroup OBJECT-GROUP
OBJECTS {
midcomSessionIndexNext,
midcomSessionRuleGroupIndex,
midcomSessionRuleStorageTime,
midcomSessionRuleIndexNext,
midcomSessionCreateRule,
midcomSessionStorageType,
midcomSessionRowStatus
}
STATUS current
DESCRIPTION
"A collection of objects providing information about
MIDCOM sessions."
::= { midcomGroups 2 }
midcomRuleGroup OBJECT-GROUP
OBJECTS {
midcomRuleAdminStatus,
midcomRuleOperStatus,
midcomRuleStorageType,
midcomRuleStorageTime,
midcomRuleError,
midcomRuleNatService,
midcomRuleInternalIpVersion,
midcomRuleInternalIpAddr,
midcomRuleInternalPort,
midcomRuleInsideIpVersion,
midcomRuleInsideIpAddr,
midcomRuleInsidePort,
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midcomRuleInsideInterface,
midcomRuleOutsideIpVersion,
midcomRuleOutsideIpAddr,
midcomRuleOutsidePort,
midcomRuleOutsideInterface,
midcomRuleExternalIpVersion,
midcomRuleExternalIpAddr,
midcomRuleExternalPort,
midcomRuleTransportProtocol,
midcomRulePortRange,
midcomRulePortParity,
midcomRuleFlowDirection,
midcomRuleLifetime
}
STATUS current
DESCRIPTION
"A collection of objects providing information about
policy rules."
::= { midcomGroups 3 }
midcomGroupGroup OBJECT-GROUP
OBJECTS {
midcomGroupLifetime
}
STATUS current
DESCRIPTION
"A collection of objects providing information about
policy rule groups."
::= { midcomGroups 4 }
midcomNotificationsGroup OBJECT-GROUP
OBJECTS {
midcomSessionTermination,
midcomRuleEvent,
midcomGroupEvent
}
STATUS current
DESCRIPTION
"The notifications emitted by the midcomMIB."
::= { midcomGroups 5 }
END
7. Usage Examples
This section presents some examples that explain how a manager can
use the MIDCOM MIB defined in this memo. The purpose of these
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examples is to explain the steps that are normally used to perform
MIDCOM transactions. For each MIDCOM transaction defined in the
MIDCOM semantics in RFC XXXX, a sequence of SNMP operations is
described, which realizes the transaction.
We see three different ways, a MIDCOM agent can choose to operate on
the MIDCOM MIB. The first one is in line with the MIDCOM semantics.
It models MIDCOM transactions as described in section 4.2 using SNMP
notifications for signaling completion of processing a transaction
from the MIDCOM MIB implementation to the MIDCOM agent.
The second way uses notifications in configuration transactions only
in 'unexpected' cases, when a request failes. The third one does not
use notifications at all in configuration transaction. We describe
the realization of MIDCOM transactions for the first way of operating
on the MIDCOM MIB. For the other two ways, just the differences to
the first ways are summarized at the end of this section.
7.1. Session Establishment (SE)
This example explains the steps performed by an SNMP manager to
establish a MIDCOM session.
1. The MIDCOM agent first checks the middlebox capabilities by
reading objects in the midcomCapabilities group.
2. The MIDCOM agent reads the midcomSessionNextIndex object in order
to receive an index for creating a session.
3. The manager creates a row in the midcomSessionTable by issuing an
SNMP set-request. The midcomSessionRowStatus object is set to
createAndWait(5). The new row is indexed by the MIDCOM agent's
USM user name and by the index read from the
midcomSessionNextIndex object in step 2.
4. If the MIDCOM agent wants to have policies stored in the
midcomRuleTable for some time after they are terminated, then it
sets the midcomSessionRuleStorageTime object to the desired value.
Otherwise, the default value of zero will be applied to the
storage time of entries in the midcomRuleTable as long as the
MIDCOM agent does not change this object.
5. If the agent wants to have all policy rules it creates to be
member of the same policy rule group, then the MIDCOM agent should
set the midcomSessionRuleGroupIndex to the group index that is to
be used.
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7.2. Session Termination (ST)
This example explains the steps performed by an SNMP manager to
terminate a MIDCOM session.
1. The manager sends an SNMP set-request to change the
midcomSessionRowStatus object to destroy(6). This will remove the
row from the midcomSessionTable but not have an effect on entries
in the midcomRuleTable created from this session.
7.3. Asynchronous Session Termination (AST)
At any time, the MIDCOM MIB implementation may terminate a session.
Only two steps are required for performing this transaction.
1. The MIDCOM MIB implementation sends a midcomSessionTermination
notification to the SNMP manager owning the session.
2. The MIDCOM MIB implementation removes the corresponding row of the
midcomSessionTable. This does not affect entries in other tables.
7.4. Policy Reserve Rule (PRR)
This example explains the steps performed by an SNMP manager to
establish a policy reserve rule.
1. If the new policy rule should become a member of an already
existing policy rule group, then the SNMP manager sets the
midcomSessionGroupIndex object to the index of that group.
Otherwise, it sets this object to 0.
2. The SNMP manager reads the midcomSessionRuleNextIndex for an open
entry in the modcomSessionTable in order to receive an object
identifier for creating a new entry in the midcomRuleTable.
3. The SNMP manager sets the midcomSessionCreateRule object to the
value read in step 2. This creates a new row in the
midcomRuleTable that is addressed by the object idenitfier written
to the midcomSessionCreateRule object.
4. The SNMP manager sets the following objects in the new row of the
midcomRuleTable to specify all request parameters of the PRR
transaction:
- midcomRuleNatService
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideInterface
- midcomRuleOutsideInterface
- midcomRuleExternalIpVersion
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- midcomRuleTransportProtocol
- midcomRulePortRange
- midcomRulePortParity
- midcomRuleLifeime
5. The SNMP manager sets the midcomRuleAdminStatus objects in the new
row of the midcomRuleTable to reserved(1).
6. The SNMP manager waits for a midcomRuleEvent notification
concerning the new row in the midcomSessionTable.
7. After receiving the midcomRuleEvent notification SNMP manager
checks the lifetime value carried by the notification. If it is
greater than 0, the SNMP manager read all positive reply
parameters of the PRR transaction:
- midcomRuleInsideIpAddr
- midcomRuleInsidePort
- midcomRuleOutsideIpAddr
- midcomRuleOutsidePort
- midcomRuleLifetime
If the lifetime equals 0, then SNMP manager reads the
midcomRuleOperStatus and the midcomRuleError in order to analyze
the failure reason.
7.5. Policy Enable Rule (PER) after PRR
This example explains the steps performed by an SNMP manager to
establish a policy enable rule after a corresponding policy reserve
rule was already established.
1. The SNMP manager sets the following objects in the row of the
established PRR in the midcomRuleTable to specify all request
parameters of the PER transaction:
- midcomRuleExternalIpAddr
- midcomRuleExternalPort
- midcomRulePortParity
- midcomRuleFlowDirection
2. The SNMP manager sets the midcomRuleAdminStatus objects in the row
of the established PRR in the midcomRuleTable to enabled(1).
3. The SNMP manager waits for a midcomRuleEvent notification
concerning the new row in the midcomSessionTable.
4. After receiving the midcomRuleEvent notification SNMP manager
checks the lifetime value carried by the notification. If it is
greater than 0, the SNMP manager read all positive reply
parameters of the PER transaction:
- midcomRuleInsideIpAddr
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- midcomRuleInsidePort
- midcomRuleOutsideIpAddr
- midcomRuleOutsidePort
- midcomRuleLifetime
If the lifetime equals 0, then SNMP manager reads the
midcomRuleOperStatus and the midcomRuleError in order to analyze
the failure reason.
7.6. Policy Enable Rule (PER) without previous PRR
This example explains the steps performed by an SNMP manager to
establish a policy enable rule for which no PRR transaction has been
performed before.
1. Identical to step 1 for PRR.
2. Identical to step 2 for PRR.
3. Identical to step 3 for PRR.
4. The SNMP manager sets the following objects in the new row of the
midcomRuleTable to specify all request parameters of the PER
transaction:
- midcomRuleInternalIpVersion
- midcomRuleInternalIpAddr
- midcomRuleInternalPort
- midcomRuleInsideInterface
- midcomRuleOutsideInterface
- midcomRuleExternalIpVersion
- midcomRuleExternalIpAddr
- midcomRuleExternalPort
- midcomRuleTransportProtocol
- midcomRulePortRange
- midcomRulePortParity
- midcomRuleFlowDirection
- midcomRuleLifetime
5. The SNMP manager sets the midcomRuleAdminStatus objects in the new
row of the midcomRuleTable to enabled(1).
6. Identical to step 6 for PRR.
7. After receiving the midcomRuleEvent notification SNMP manager
checks the lifetime value carried by the notification. If it is
greater than 0, the SNMP manager read all positive reply
parameters of the PRR transaction:
- midcomRuleInsideIpAddr
- midcomRuleInsidePort
- midcomRuleOutsideIpAddr
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- midcomRuleOutsidePort
- midcomRuleFlowDirection
- midcomRuleLifetime
If the lifetime equals 0, then SNMP manager reads the
midcomRuleOperStatus and the midcomRuleError in order to analyze
the failure reason.
7.7. Policy Rule Lifetime Change (RLC)
This example explains the steps performed by an SNMP manager to
change the lifetime of a policy rule. Changing the lifetime to 0
implies terminating the policy rule.
1. The SNMP manager issues a set-request for writing the desired
lifetime to the midcomRuleLifetime object in the corresponding row
of the midcomRuleTable.
2. The SNMP manager waits for a midcomRuleEvent notification
concerning the corresponding row in the midcomRuleTable.
3. After receiving the midcomRuleEvent notification SNMP manager
checks the lifetime value carried by the notification.
7.8. Policy Rule List (PRL)
The SNMP agent can browse the list of policy rules by browsing the
midcomRuleTable. For each observed row in this table, the SNMP agent
should check the midcomRuleOperStatus in order to find out, if the
row contains information about an established policy rule or of a
rule that is under construction or already terminated.
7.9. Policy Rule Status (PRS)
The SNMP agent can retrieve all status information and properties of
a policy rule by reading the managed objects in the corresponding row
of the midcomRuleTable.
7.10. Asynchronous Policy Rule Event (ARE)
At any time, the MIDCOM MIB implementation may terminate a policy
rule. in this case two steps are required for performing this
transaction:
1. The MIDCOM MIB implementation sends a midcomRuleEvent notification
containing a lifetime value of 0 to the SNMP manager owning the
session.
2. If the midcomRuleStorageTime object in the corresponding row of
the midcomRuleTable has a value of 0 then the MIDCOM MIB
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implementation removes the row from the table. Otherwise, it
changes in this row the midcomRuleLifetime object to 0 and the
midcomRuleOperStatus object to terminated(13).
The procedure is the same if the lifetime of a policy rule expires.
The only difference is that the midcomRuleOperStatus object is set to
timedOut(11) instead of terminated(13).
7.11. Group Lifetime Change (GLC)
This example explains the steps performed by an SNMP manager to
change the lifetime of a policy rule group. Changing the lifetime to
0 implies terminating all member policies of the group.
1. The SNMP manager issues a set-request for writing the desired
lifetime to the midcomGroupLifetime object in the corresponding
row of the midcomGroupTable.
2. The SNMP manager waits for a midcomGroupEvent notification
concerning the corresponding row in the midcomGroupTable.
3. After receiving the midcomRuleEvent notification SNMP manager
checks the lifetime value carried by the notification.
7.12. Group List (GL)
The SNMP agent can browse the list of policy rule groups by browsing
the midcomGroupTable. For each observed row in this table, the SNMP
agent should check the midcomGroupLifetime in order to find out, if
the group does contain established policies.
7.13. Group Status (GS)
The SNMP agent can retrieve all member policies of a group by
browsing the midcomRuleTable using the midcomGroupIndex of the
particular group. For retriving the remaining lifetime of the group,
the SNMP agent reads the midcomGroupLifetime object in the
corresponding row of the midcomGroupTable.
7.14. Using Notifications For Negative Replies Only
To be done.
7.15. Not Using Notifications For Replies
To be done.
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8. Security Considerations
Still to be completed. Very important for this module! More text
here ....
SNMP versions prior to SNMPv3 did not include adequate security.
Even if the network itself is secure (for example by using IPSec),
even then, there is no control as to who on the secure network is
allowed to access and GET/SET (read/change/create/delete) the objects
in this MIB module.
It is REQUIRED that implementers consider the security features as
provided by the SNMPv3 framework (see [RFC3410], section 8),
including full support for the SNMPv3 cryptographic mechanisms (for
authentication and privacy).
For implementations of the MIDCOM MIB it is REQUIRED to deploy SNMPv3
and to enable cryptographic security. It is then a customer/operator
responsibility to ensure that the SNMP entity giving access to an
instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them.
9. Open Issues
- notification identifiers, transaction identifiers
- effect on other MIB modules missing
- security considerations not complete
- discuss atomicity of PRR and PER transactions
- grop lifetime: ref to semantics not appropriate
- rule lifetime: ref to semantics not appropriate
- centi-seconds or seconds?
- session index requred?
- DEFVAL for A0, A1, A2, A3
- collision of midcomRulePortParity usage
- redundant inside/outside IpVersions
- missing description of midcomsessionIndexNext
- means for configuring which notifications to receive
- examples for using less notifications
- a set of issues raised by David Harrington
10. Normative References
[RFC3303] Srisuresh, P., Kuthan, J., Rosenberg, J., Molitor, A. and A.
Rayhan, "Middlebox communication architecture and
framework", RFC 3303, August 2002.
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[RFC3304] Swale, R.P., Mart, P.A., Sijben, P., Brimm, S. and M. Shore,
"Middlebox Communications (midcom) Protocol Requirements",
RFC 3304, August 2002.
[RFCXXXX] Stiemerling, M., Quittek, J. and T. Tailor, "Middlebox
Communications (midcom) protocol semantics", RFC XXXX,
YYYYmonth 2003, <draft-ietf-midcom-semantics-03.txt>.
[RFC2578] 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.
[RFC2579] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Textual Conventions for SMIv2",
STD 58, RFC 2579, April 1999.
[RFC2580] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Conformance Statements for
SMIv2", STD 58, RFC 2580, April 1999.
[RFC3411] Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture
for Describing Simple Network Management Protocol (SNMP)
Management Frameworks", STD 62, RFC 3411, December 2002.
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, June 2000.
[RFC2574] Blumenthal, U., and B. Wijnen, "User-based Security Model
(USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", RFC 2574, April 1999.
11. Informative References
[RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
[NAT-TERM] Srisuresh,P., and Holdrege, M., "IP Network Translator (NAT)
Terminology and Considerations", RFC 2663, August 1999.
[RFC2246] Dierks, T., Allen, C., "The TLS Protocol Version 1.0", RFC
2246, January 1999.
[RFC2402] Kent, S., and Atkinson, R., "IP Authentication Header", RFC
2402, November 1998.
[RFC2406] Kent, S., and Atkinson, R., "IP Encapsulating Security
Payload (ESP)", RFC 2406, November 1998.
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12. Authors' Addresses
Juergen Quittek
NEC Europe Ltd.
Network Laboratories
Kurfuersten-Anlage 34
69115 Heidelberg
Germany
Phone: +49 6221 90511-15
EMail: quittek@ccrle.nec.de
Martin Stiemerling
NEC Europe Ltd.
Network Laboratories
Kurfuersten-Anlage 34
69115 Heidelberg
Germany
Phone: +49 6221 90511-13
Email: stiemerling@ccrle.nec.de
13. Full Copyright Statement
Copyright (C) The Internet Society (2003). 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
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Internet-Draft MIDCOM MIB October 2003
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