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 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Distribution of this document is unlimited. 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. Quittek, Stiemerling [Page 1] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 2] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 3] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 4] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 5] Internet-Draft MIDCOM MIB October 2003 +--------------+ 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. Quittek, Stiemerling [Page 6] Internet-Draft MIDCOM MIB October 2003 +--------------+ 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. Quittek, Stiemerling [Page 7] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 8] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 9] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 10] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 11] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 12] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 13] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 14] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 15] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 16] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 17] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 18] Internet-Draft MIDCOM MIB October 2003 -- 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, Quittek, Stiemerling [Page 19] Internet-Draft MIDCOM MIB October 2003 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, Quittek, Stiemerling [Page 20] Internet-Draft MIDCOM MIB October 2003 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 } Quittek, Stiemerling [Page 21] Internet-Draft MIDCOM MIB October 2003 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 } Quittek, Stiemerling [Page 22] Internet-Draft MIDCOM MIB October 2003 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 } Quittek, Stiemerling [Page 23] Internet-Draft MIDCOM MIB October 2003 ::= { 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 Quittek, Stiemerling [Page 24] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 25] Internet-Draft MIDCOM MIB October 2003 "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, Quittek, Stiemerling [Page 26] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 27] Internet-Draft MIDCOM MIB October 2003 - 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. Quittek, Stiemerling [Page 28] Internet-Draft MIDCOM MIB October 2003 - 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 Quittek, Stiemerling [Page 29] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 30] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 31] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 32] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 33] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 34] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 35] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 36] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 37] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 38] Internet-Draft MIDCOM MIB October 2003 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." Quittek, Stiemerling [Page 39] Internet-Draft MIDCOM MIB October 2003 ::= { 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 Quittek, Stiemerling [Page 40] Internet-Draft MIDCOM MIB October 2003 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, Quittek, Stiemerling [Page 41] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 42] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 43] Internet-Draft MIDCOM MIB October 2003 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 Quittek, Stiemerling [Page 44] Internet-Draft MIDCOM MIB October 2003 - 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 Quittek, Stiemerling [Page 45] Internet-Draft MIDCOM MIB October 2003 - 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 Quittek, Stiemerling [Page 46] Internet-Draft MIDCOM MIB October 2003 - 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 Quittek, Stiemerling [Page 47] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 48] Internet-Draft MIDCOM MIB October 2003 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. Quittek, Stiemerling [Page 49] Internet-Draft MIDCOM MIB October 2003 [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, . [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. Quittek, Stiemerling [Page 50] Internet-Draft MIDCOM MIB October 2003 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 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 Quittek, Stiemerling [Page 51] Internet-Draft MIDCOM MIB October 2003 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Quittek, Stiemerling [Page 52]