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Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Historic RFC: RFC 1157 (ref. '2') ** Downref: Normative reference to an Informational RFC: RFC 1215 (ref. '4') ** Downref: Normative reference to an Informational RFC: RFC 1303 (ref. '5') ** Downref: Normative reference to an Historic RFC: RFC 1901 (ref. '6') ** Obsolete normative reference: RFC 1905 (ref. '10') (Obsoleted by RFC 3416) ** Obsolete normative reference: RFC 1906 (ref. '11') (Obsoleted by RFC 3417) ** Obsolete normative reference: RFC 1907 (ref. '12') (Obsoleted by RFC 3418) ** Obsolete normative reference: RFC 1908 (ref. '13') (Obsoleted by RFC 2576) ** Obsolete normative reference: RFC 2089 (ref. '14') (Obsoleted by RFC 2576) ** Obsolete normative reference: RFC 2571 (ref. '16') (Obsoleted by RFC 3411) ** Obsolete normative reference: RFC 2572 (ref. '17') (Obsoleted by RFC 3412) ** Obsolete normative reference: RFC 2573 (ref. '18') (Obsoleted by RFC 3413) ** Obsolete normative reference: RFC 2574 (ref. '19') (Obsoleted by RFC 3414) ** Obsolete normative reference: RFC 2575 (ref. '20') (Obsoleted by RFC 3415) Summary: 21 errors (**), 0 flaws (~~), 8 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 INTERNET-DRAFT Rob Frye 2 MCI WorldCom 3 David B. Levi 4 Nortel Networks 5 Shawn A. Routhier 6 Integrated Systems Inc. 7 Bert Wijnen 8 IBM T.J. Watson Research 9 11 Oct 1999 11 Coexistence between Version 1, Version 2, and Version 3 12 of the Internet-standard Network Management Framework 13 15 Status of this Memo 17 This document is an Internet-Draft and is in full conformance with 18 all provisions of Section 10 of RFC2026. Internet-Drafts are working 19 documents of the Internet Engineering Task Force (IETF), its areas, 20 and its working groups. Note that other groups may also distribute 21 working documents as Internet-Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/ietf/1id-abstracts.txt 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html 34 Copyright Notice 36 Copyright (C) The Internet Society (1999). All Rights Reserved. 38 Abstract 40 The purpose of this document is to describe coexistence between 41 version 3 of the Internet-standard Network Management Framework, 42 (SNMPv3), version 2 of the Internet-standard Network Management 43 Framework (SNMPv2), and the original Internet-standard Network 44 Management Framework (SNMPv1). This document obsoletes RFC 1908 [13] 45 and RFC2089 [14]. 47 Table Of Contents 49 1 Overview ..................................................... 4 50 1.1 SNMPv1 ..................................................... 4 51 1.2 SNMPv2 ..................................................... 5 52 1.3 SNMPv3 ..................................................... 6 53 1.4 SNMPv1 and SNMPv2 Access to MIB Data ....................... 6 54 2 SMI and Management Information Mappings ...................... 8 55 2.1 MIB Modules ................................................ 8 56 2.1.1 Object Definitions ....................................... 8 57 2.1.2 Trap and Notification Definitions ........................ 11 58 2.2 Compliance Statements ...................................... 11 59 2.3 Capabilities Statements .................................... 12 60 3 Translating Notifications Parameters ......................... 13 61 3.1 Translating SNMPv1 Notification Parameters to SNMPv2 62 Notification Parameters ................................... 14 63 3.2 Translating SNMPv2 Notification Parameters to SNMPv1 64 Notification Parameters ................................... 15 65 4 Approaches to Coexistence in a Multi-lingual Network ......... 18 66 4.1 Multi-lingual implementations .............................. 18 67 4.1.1 Command Generator ........................................ 18 68 4.1.2 Command Responder ........................................ 19 69 4.1.2.1 Handling Counter64 ..................................... 19 70 4.1.2.2 Mapping SNMPv2 Exceptions .............................. 20 71 4.1.2.2.1 Mapping noSuchObject and noSuchInstance .............. 21 72 4.1.2.2.2 Mapping endOfMibView ................................. 21 73 4.1.2.3 Processing An SNMPv1 GetRequest ........................ 21 74 4.1.2.4 Processing An SNMPv1 GetNextRequest .................... 22 75 4.1.2.5 Processing An SNMPv1 SetRequest ........................ 24 76 4.1.3 Notification Originator .................................. 24 77 4.1.4 Notification Receiver .................................... 25 78 4.2 Proxy Implementations ...................................... 25 79 4.2.1 Upstream Version Greater Than Downstream Version ......... 26 80 4.2.2 Upstream Version Less Than Downstream Version ............ 27 81 4.3 Error Status Mappings ...................................... 28 82 5 Message Processing Models and Security Models ................ 30 83 5.1 Mappings ................................................... 30 84 5.2 The SNMPv1 MP Model and SNMPv1 Community-based Security 85 Model ..................................................... 30 86 5.2.1 Processing An Incoming Request ........................... 31 87 5.2.2 Generating An Outgoing Response .......................... 33 88 5.2.3 Generating An Outgoing Notification ...................... 33 89 5.3 The SNMP Community MIB Module .............................. 34 90 6 Intellectual Property ........................................ 45 91 7 Acknowledgments .............................................. 46 92 8 Security Considerations ...................................... 47 93 9 References ................................................... 48 94 10 Editor's Address ............................................ 50 95 A. Full Copyright Statement .................................... 51 97 1. Overview 99 The purpose of this document is to describe coexistence between 100 version 3 of the Internet-standard Network Management Framework, 101 termed the SNMP version 3 framework (SNMPv3), version 2 of the 102 Internet-standard Network Management Framework, termed the SNMP 103 version 2 framework (SNMPv2), and the original Internet-standard 104 Network Management Framework (SNMPv1). 106 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 107 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 108 document are to be interpreted as described in RFC2119 [15]. 110 There are four general aspects of coexistence described in this 111 document. Each of these is described in a separate section: 113 - Conversion of MIB documents between SMIv1 and SMIv2 formats is 114 documented in section 2. 116 - Mapping of notification parameters is documented in section 3. 118 - Approaches to coexistence between entities which support the 119 various versions of SNMP in a multi-lingual network is 120 documented in section 4. This section addresses the 121 processing of protocol operations in multi-lingual 122 implementations, as well as behaviour of proxy 123 implementations. 125 - The SNMPv1 Message Processing Model and Community-Based 126 Security Model, which provides mechanisms for adapting SNMPv1 127 into the View-Based Access Control Model (VACM) [20], is 128 documented in section 5 (this section also addresses the 129 SNMPv2c Message Processing Model and Community-Based Security 130 Model). 132 1.1. SNMPv1 134 SNMPv1 is defined by these documents: 136 - STD 15, RFC 1157 [2] which defines the Simple Network 137 Management Protocol (SNMPv1), the protocol used for network 138 access to managed objects. 140 - STD 16, RFC 1155 [1] which defines the Structure of Management 141 Information (SMIv1), the mechanisms used for describing and 142 naming objects for the purpose of management. 144 - STD 16, RFC 1212 [3] which defines a more concise description 145 mechanism, which is wholly consistent with the SMIv1. 147 - RFC 1215 [4] which defines a convention for defining Traps for 148 use with the SMIv1. 150 Note that throughout this document, the term 'SMIv1' is used. This 151 term generally refers to the information presented in RFC 1155, RFC 152 1212, and RFC 1215. 154 1.2. SNMPv2 156 SNMPv2 is defined by these documents: 158 - STD 58, RFC 2578 which defines Version 2 of the Structure of 159 Management Information (SMIv2) [7]. 161 - STD 58, RFC 2579 which defines common MIB "Textual 162 Conventions" [8]. 164 - STD 58, RFC 2580 which defines Conformance Statements and 165 requirements for defining agent and manager capabilities [9]. 167 - RFC 1905 which defines the Protocol Operations used in 168 processing [10]. 170 - RFC 1906 which defines the Transport Mappings used "on the 171 wire" [11]. 173 - RFC 1907 which defines the basic Management Information Base 174 for monitoring and controlling some basic common functions of 175 SNMP entities [12]. 177 Note that SMIv2 as used throughout this document refers to the first 178 three documents listed above (RFCs 2578, 2579, and 2580). 180 The following document augments the definition of SNMPv2: 182 - RFC 1901 [6] is an Experimental definition for using SNMPv2 183 PDUs within a community-based message wrapper. This is 184 referred to throughout this document as SNMPv2c. 186 1.3. SNMPv3 188 SNMPv3 is defined by these documents: 190 - RFC 2571 which defines an Architecture for Describing SNMP 191 Management Frameworks [16]. 193 - RFC 2572 which defines Message Processing and Dispatching 194 [17]. 196 - RFC 2573 which defines various SNMP Applications [18]. 198 - RFC 2574 which defines the User-based Security Model (USM), 199 providing for both Authenticated and Private (encrypted) SNMP 200 messages [19]. 202 - RFC 2575 which defines the View-based Access Control Model 203 (VACM), providing the ability to limit access to different MIB 204 objects on a per-user basis [20]. 206 SNMPv3 also uses the SNMPv2 definitions of RFCs 1905 through 1907 and 207 the SMIv2 definitions of 2578 through 2580 described above. 209 1.4. SNMPv1 and SNMPv2 Access to MIB Data 211 In several places, this document refers to 'SNMPv1 Access to MIB 212 Data' and 'SNMPv2 Access to MIB Data'. These terms refer to the part 213 of an SNMP agent which actually accesses instances of MIB objects, 214 and which actually initiates generation of notifications. 215 Differences between the two types of access to MIB data are: 217 - Error-status values generated. 219 - Generation of exception codes. 221 - Use of the Counter64 data type. 223 - The format of parameters provided when a notification is 224 generated. 226 SNMPv1 access to MIB data may generate SNMPv1 error-status values, 227 will never generate exception codes nor use the Counter64 data type, 228 and will provide SNMPv1 format parameters for generating 229 notifications. Note also that SNMPv1 access to MIB data will 230 actually never generate a readOnly error (a noSuchName error would 231 always occur in the situation where one would expect a readOnly 232 error). 234 SNMPv2 access to MIB data may generate SNMPv2 error-status values, 235 may generate exception codes, may use the Counter64 data type, and 236 will provide SNMPv2 format parameters for generating notifications. 237 Note that SNMPv2 access to MIB data will never generate readOnly, 238 noSuchName, or badValue errors. 240 Note that a particular multi-lingual implementation may choose to 241 implement all access to MIB data as SNMPv2 access to MIB data, and 242 perform the translations described herein for SNMPv1-based 243 transactions. 245 2. SMI and Management Information Mappings 247 The SMIv2 approach towards describing collections of managed objects 248 is nearly a proper superset of the approach defined in the SMIv1. 249 For example, both approaches use an adapted subset of ASN.1 (1988) 250 [11] as the basis for a formal descriptive notation. Indeed, one 251 might note that the SMIv2 approach largely codifies the existing 252 practice for defining MIB modules, based on extensive experience with 253 the SMIv1. 255 The following sections consider the three areas: MIB modules, 256 compliance statements, and capabilities statements. 258 2.1. MIB Modules 260 MIB modules defined using the SMIv1 may continue to be used with 261 protocol versions which use SNMPv2 PDUs. However, for the MIB 262 modules to conform to the SMIv2, the following changes SHALL be made: 264 2.1.1. Object Definitions 266 In general, conversion of a MIB module does not require the 267 deprecation of the objects contained therein. If the semantics of an 268 object truly changes, the object SHALL be deprecated, otherwise 269 deprecation is not required. 271 (1) The IMPORTS statement MUST reference SNMPv2-SMI, instead of 272 RFC1155-SMI and RFC-1212. 274 (2) The MODULE-IDENTITY macro MUST be invoked immediately after any 275 IMPORTs statement. 277 (3) For any object with an integer-valued SYNTAX clause, in which the 278 corresponding INTEGER does not have a range restriction (i.e., the 279 INTEGER has neither a defined set of named-number enumerations nor 280 an assignment of lower- and upper-bounds on its value), the object 281 MUST have the value of its SYNTAX clause changed to Integer32, or 282 have an appropriate range specified. 284 (4) For any object with a SYNTAX clause value of Counter, the object 285 MUST have the value of its SYNTAX clause changed to Counter32. 287 (5) For any object with a SYNTAX clause value of Gauge, the object MUST 288 have the value of its SYNTAX clause changed to Gauge32, or 289 Unsigned32 where appropriate. 291 (6) For all objects, the ACCESS clause MUST be replaced by a MAX-ACCESS 292 clause. The value of the MAX-ACCESS clause SHALL be the same as 293 that of the ACCESS clause unless some other value makes "protocol 294 sense" as the maximal level of access for the object. In 295 particular, object types for which instances can be explicitly 296 created by a protocol set operation, SHALL have a MAX-ACCESS clause 297 of "read-create". If the value of the ACCESS clause is "write- 298 only", then the value of the MAX-ACCESS clause MUST be "read- 299 write", and the DESCRIPTION clause SHALL note that reading this 300 object will result in implementation-specific results. Note that 301 in SMIv1, the ACCESS clause specifies the minimal required access, 302 while in SMIv2, the MAX-ACCESS clause specifies the maximum allowed 303 access. This should be considered when converting an ACCESS clause 304 to a MAX-ACCESS clause. 306 (7) For all objects, if the value of the STATUS clause is "mandatory" 307 or "optional", the value MUST be replaced with "current", 308 "deprecated", or "obsolete" depending on the current usage of such 309 objects. 311 (8) For any object not containing a DESCRIPTION clause, the object MUST 312 have a DESCRIPTION clause defined. 314 (9) For any object corresponding to a conceptual row which does not 315 have an INDEX clause, the object MUST have either an INDEX clause 316 or an AUGMENTS clause defined. 318 (10) If any INDEX clause contains a reference to an object with a syntax 319 of NetworkAddress, then a new object MUST be created and placed in 320 this INDEX clause immediately preceding the object whose syntax is 321 NetworkAddress. This new object MUST have a syntax of INTEGER, it 322 MUST be not-accessible, and its value MUST always be 1. 324 (11) For any object with a SYNTAX of NetworkAddress, the SYNTAX MUST be 325 changed to IpAddress. Note that the use of NetworkAddress in new 326 MIB documents is strongly discouraged (in fact, new MIB documents 327 should be written using SMIv2, which does not define 328 NetworkAddress). 330 (12) For any object containing a DEFVAL clause with an OBJECT IDENTIFIER 331 value which is expressed as a collection of sub-identifiers, the 332 value MUST be changed to reference a single ASN.1 identifier. This 333 may require defining a series of new administrative assignments 334 (OBJECT IDENTIFIERS) in order to define the single ASN.1 335 identifier. 337 (13) One or more OBJECT-GROUPS MUST be defined, and related objects 338 SHOULD be collected into appropriate groups. Note that SMIv2 339 requires all OBJECT-TYPEs to be a member of at least one OBJECT- 340 GROUP. 342 Other changes are desirable, but not necessary: 344 (1) Creation and deletion of conceptual rows is inconsistent using the 345 SMIv1. The SMIv2 corrects this. As such, if the MIB module 346 undergoes review early in its lifetime, and it contains conceptual 347 tables which allow creation and deletion of conceptual rows, then 348 the objects relating to those tables MAY be deprecated and replaced 349 with objects defined using the new approach. The approach base on 350 SMIv2 can be found in section 7 of RFC2578 [7], and the RowStatus 351 and StorageType TEXTUAL-CONVENTIONs are described in section 2 of 352 RFC2579 [8]. 354 (2) For any object with a string-valued SYNTAX clause, in which the 355 corresponding OCTET STRING does not have a size restriction (i.e., 356 the OCTET STRING has no assignment of lower- and upper-bounds on 357 its length), the bounds for the size of the object SHOULD be 358 defined. 360 (3) All textual conventions informally defined in the MIB module SHOULD 361 be redefined using the TEXTUAL-CONVENTION macro. Such a change 362 would not necessitate deprecating objects previously defined using 363 an informal textual convention. 365 (4) For any object which represents a measurement in some kind of 366 units, a UNITS clause SHOULD be added to the definition of that 367 object. 369 (5) For any conceptual row which is an extension of another conceptual 370 row, i.e., for which subordinate columnar objects both exist and 371 are identified via the same semantics as the other conceptual row, 372 an AUGMENTS clause SHOULD be used in place of the INDEX clause for 373 the object corresponding to the conceptual row which is an 374 extension. 376 Finally, to avoid common errors in SMIv1 MIB modules: 378 (1) For any non-columnar object that is instanced as if it were 379 immediately subordinate to a conceptual row, the value of the 380 STATUS clause of that object MUST be changed to "obsolete". 382 (2) For any conceptual row object that is not contained immediately 383 subordinate to a conceptual table, the value of the STATUS clause 384 of that object (and all subordinate objects) MUST be changed to 385 "obsolete". 387 2.1.2. Trap and Notification Definitions 389 If a MIB module is changed to conform to the SMIv2, then each 390 occurrence of the TRAP-TYPE macro MUST be changed to a corresponding 391 invocation of the NOTIFICATION-TYPE macro: 393 (1) The IMPORTS statement MUST NOT reference RFC-1215 [4], and MUST 394 reference SNMPv2-SMI instead. 396 (2) The ENTERPRISE clause MUST be removed. 398 (3) The VARIABLES clause MUST be renamed to the OBJECTS clause. 400 (4) A STATUS clause MUST be added, with an appropriate value. Normally 401 the value should be 'current,' although 'deprecated' or 'obsolete' 402 may be used as needed. 404 (5) The value of an invocation of the NOTIFICATION-TYPE macro is an 405 OBJECT IDENTIFIER, not an INTEGER, and MUST be changed accordingly. 406 Specifically, if the value of the ENTERPRISE clause is not 'snmp' 407 then the value of the invocation SHALL be the value of the 408 ENTERPRISE clause extended with two sub-identifiers, the first of 409 which has the value 0, and the second has the value of the 410 invocation of the TRAP-TYPE. If the value of the ENTERPRISE clause 411 is 'snmp', then the value of the invocation of the NOTIFICATION- 412 TYPE macro SHALL be mapped in the same manner as described in 413 section 3.1 in this document. 415 (6) A DESCRIPTION clause MUST be added, if not already present. 417 (7) One or more NOTIFICATION-GROUPs MUST be defined, and related 418 notifications MUST be collected into those groups. Note that SMIv2 419 requires that all NOTIFICATION-TYPEs be a member of at least one 420 NOTIFICATION-GROUP. 422 2.2. Compliance Statements 424 For those information modules which are "standards track", a 425 corresponding invocation of the MODULE-COMPLIANCE macro and related 426 OBJECT-GROUP macros MUST be included within the information module 427 (or in a companion information module), and any commentary text in 428 the information module which relates to compliance SHOULD be removed. 429 Typically this editing can occur when the information module 430 undergoes review. 432 Note that a MODULE-COMPLIANCE statement is not required for a MIB 433 document that is not on the standards track (for example, an 434 enterprise MIB), though it may be useful in some circumstances to 435 define a MODULE-COMPLIANCE statement for such a MIB document. 437 2.3. Capabilities Statements 439 RFC1303 [5] uses the MODULE-CONFORMANCE macro to describe an agent's 440 capabilities with respect to one or more MIB modules. Converting 441 such a description for use with the SMIv2 requires these changes: 443 (1) The macro name AGENT-CAPABILITIES SHOULD be used instead of MODULE- 444 CONFORMANCE. 446 (2) The STATUS clause SHOULD be added, with a value of 'current'. 448 (3) All occurrences of the CREATION-REQUIRES clause MUST either be 449 omitted if appropriate, or be changed such that the semantics are 450 consistent with RFC2580 [9]. 452 In order to ease coexistence, object groups defined in an SMIv1 453 compliant MIB module may be referenced by the INCLUDES clause of an 454 invocation of the AGENT-CAPABILITIES macro: upon encountering a 455 reference to an OBJECT IDENTIFIER subtree defined in an SMIv1 MIB 456 module, all leaf objects which are subordinate to the subtree and 457 have a STATUS clause value of mandatory are deemed to be INCLUDEd. 458 (Note that this method is ambiguous when different revisions of an 459 SMIv1 MIB have different sets of mandatory objects under the same 460 subtree; in such cases, the only solution is to rewrite the MIB using 461 the SMIv2 in order to define the object groups unambiguously.) 463 3. Translating Notifications Parameters 465 This section describes how parameters used for generating 466 notifications are translated between the format used for SNMPv1 467 notification protocol operations and the format used for SNMPv2 468 notification protocol operations. The parameters used to generate a 469 notification are called 'notification parameters.' The format of 470 parameters used for SNMPv1 notification protocol operations is 471 refered to in this document as 'SNMPv1 notification parameters.' The 472 format of parameters used for SNMPv2 notification protocol operations 473 is refered to in this document as 'SNMPv2 notification parameters.' 475 The situations where notification parameters MUST be translated are: 477 - When an entity generates a set of notification parameters in a 478 particular format, and the configuration of the entity 479 indicates that the notification must be sent using an SNMP 480 message version that requires the other format for 481 notification parameters. 483 - When a proxy receives a notification that was sent using an 484 SNMP message version that requires one format of notification 485 parameters, and must forward the notification using an SNMP 486 message version that requires the other format of notification 487 parameters. 489 In addition, it MAY be desirable to translate notification parameters 490 in a notification receiver application in order to present 491 notifications to the end user in a consistent format. 493 Note that for the purposes of this section, the set of notification 494 parameters is independent of whether the notification is to be sent 495 as a trap or an inform. 497 SNMPv1 notification parameters consist of: 499 - An enterprise parameter (OBJECT IDENTIFIER). 501 - An agent-addr parameter (NetworkAddress). 503 - A generic-trap parameter (INTEGER). 505 - A specific-trap parameter (INTEGER). 507 - A time-stamp parameter (TimeTicks). 509 - A list of variable-bindings (VarBindList). 511 SNMPv2 notification parameters consist of: 513 - A sysUpTime parameter (TimeTicks). This appears in the first 514 variable-binding in an SNMPv2-Trap-PDU or InformRequest-PDU. 516 - An snmpTrapOID parameter (OBJECT IDENTIFIER). This appears in 517 the second variable-binding in an SNMPv2-Trap-PDU or 518 InformRequest-PDU. 520 - A list of variable-bindings (VarBindList). This refers to all 521 but the first two variable-bindings in an SNMPv2-Trap-PDU or 522 InformRequest-PDU. 524 3.1. Translating SNMPv1 Notification Parameters to SNMPv2 Notification 525 Parameters 527 The following procedure describes how to translate SNMPv1 528 notification parameters into SNMPv2 notification parameters: 530 (1) The SNMPv2 sysUpTime parameter SHALL be taken directly from the 531 SNMPv1 time-stamp parameter. 533 (2) If the SNMPv1 generic-trap parameter is 'enterpriseSpecific(6)', 534 the SNMPv2 snmpTrapOID parameter SHALL be the concatentation of the 535 SNMPv1 enterprise parameter and two additional sub-identifiers, 536 '0', and the SNMPv1 specific-trap parameter. 538 (3) If the SNMPv1 generic-trap parameter is not 539 'enterpriseSpecific(6)', the SNMPv2 snmpTrapOID parameter SHALL be 540 the corresponding trap as defined in section 2 of RFC1907 [12]: 542 generic-trap parameter snmpTrapOID.0 543 ====================== ============= 544 0 1.3.6.1.6.3.1.1.5.1 (coldStart) 545 1 1.3.6.1.6.3.1.1.5.2 (warmStart) 546 2 1.3.6.1.6.3.1.1.5.3 (linkDown) 547 3 1.3.6.1.6.3.1.1.5.4 (linkUp) 548 4 1.3.6.1.6.3.1.1.5.5 (authenticationFailure) 549 5 1.3.6.1.6.3.1.1.5.6 (egpNeighborLoss) 551 (4) The SNMPv2 variable-bindings SHALL be the SNMPv1 variable-bindings. 552 In addition, if the translation is being performed by a proxy in 553 order to forward a received trap, three additional variable- 554 bindings will be appended, if these three additional variable- 555 bindings do not already exist in the SNMPv1 variable-bindings. The 556 name portion of the first additional variable binding SHALL contain 557 snmpTrapAddress.0, and the value SHALL contain the SNMPv1 agent- 558 addr parameter. The name portion of the second additional variable 559 binding SHALL contain snmpTrapCommunity.0, and the value SHALL 560 contain the value of the community-string field from the received 561 SNMPv1 message which contained the SNMPv1 Trap-PDU. The name 562 portion of the third additional variable binding SHALL contain 563 snmpTrapEnterprise.0 [12], and the value SHALL be the SNMPv1 564 enterprise parameter. 566 3.2. Translating SNMPv2 Notification Parameters to SNMPv1 Notification 567 Parameters 569 The following procedure describes how to translate SNMPv2 570 notification parameters into SNMPv1 notification parameters: 572 (1) The SNMPv1 enterprise parameter SHALL be determined as follows: 574 - If the SNMPv2 snmpTrapOID parameter is one of the standard 575 traps as defined in RFC1907 [12], then the SNMPv1 enterprise 576 parameter SHALL be set to the value of the variable-binding in 577 the SNMPv2 variable-bindings whose name is 578 snmpTrapEnterprise.0 if that variable-binding exists. If it 579 does not exist, the SNMPv1 enterprise parameter SHALL be set 580 to the value 'snmpTraps' as defined in RFC1907 [12]. 582 - If the SNMPv2 snmpTrapOID parameter is not one of the standard 583 traps as defined in RFC1907 [12], then the SNMPv1 enterprise 584 parameter SHALL be set to the SNMPv2 snmpTrapOID parameter as 585 follows: 587 - If the next-to-last sub-identifier of the snmpTrapOID is 588 zero, then the SMIv1 enterprise SHALL be the SMIv2 589 snmpTrapOID with the last 2 sub-identifiers removed, 590 otherwise 592 - If the next-to-last sub-identifier of the snmpTrapOID is 593 non-zero, then the SMIv1 enterprise SHALL be the SMIv2 594 snmpTrapOID with the last sub-identifier removed. 596 (2) The SNMPv1 agent-addr parameter SHALL be determined based on the 597 situation in which the translation occurs. 599 - If the translation occurs within a notification originator 600 application, and the notification is to be sent over IP, the 601 SNMPv1 agent-addr parameter SHALL be set to the IP address of 602 the SNMP entity in which the notification originator resides. 603 If the notification is to be sent over some other transport, 604 the SNMPv1 agent-addr parameter SHALL be set to 0.0.0.0. 606 - If the translation occurs within a proxy application, the 607 proxy must attempt to extract the original source of the 608 notification from the variable-bindings. If the SNMPv2 609 variable-bindings contains a variable binding whose name is 610 snmpTrapAddress.0, the agent-addr parameter SHALL be set to 611 the value of that variable binding. Otherwise, the SNMPv1 612 agent-addr parameter SHALL be set to 0.0.0.0. 614 (3) If the SNMPv2 snmpTrapOID parameter is one of the standard traps as 615 defined in RFC1907 [12], the SNMPv1 generic-trap parameter SHALL be 616 set as follows: 618 snmpTrapOID.0 parameter generic-trap 619 =============================== ============ 620 1.3.6.1.6.3.1.1.5.1 (coldStart) 0 621 1.3.6.1.6.3.1.1.5.2 (warmStart) 1 622 1.3.6.1.6.3.1.1.5.3 (linkDown) 2 623 1.3.6.1.6.3.1.1.5.4 (linkUp) 3 624 1.3.6.1.6.3.1.1.5.5 (authenticationFailure) 4 625 1.3.6.1.6.3.1.1.5.6 (egpNeighborLoss) 5 627 Otherwise, the SNMPv1 generic-trap parameter SHALL be set to 6. 629 (4) If the SNMPv2 snmpTrapOID parameter is one of the standard traps as 630 defined in RFC1907 [12], the SNMPv1 specific-trap parameter SHALL 631 be set to zero. Otherwise, the SNMPv1 specific-trap parameter 632 SHALL be set to the last sub-identifier of the SNMPv2 snmpTrapOID 633 parameter. 635 (5) The SNMPv1 time-stamp parameter SHALL be taken directly from the 636 SNMPv2 sysUpTime parameter. 638 (6) The SNMPv1 variable-bindings SHALL be the SNMPv2 variable-bindings. 639 Note, however, that if the SNMPv2 variable-bindings contain any 640 objects whose type is Counter64, the translation to SNMPv1 641 notification parameters cannot be performed. In this case, the 642 notification cannot be encoded in an SNMPv1 packet (and so the 643 notification cannot be sent using SNMPv1, see section 4.1.3 and 644 section 4.2). 646 4. Approaches to Coexistence in a Multi-lingual Network 648 There are two basic approaches to coexistence in a multi-lingual 649 network, multi-lingual implementations and proxy implementations. 650 Multi-lingual implementations allow elements in a network to 651 communicate with each other using an SNMP version which both elements 652 support. This allows a multi-lingual implementation to communicate 653 with any mono-lingual implementation, regardless of the SNMP version 654 supported by the mono-lingual implementation. 656 Proxy implementations provide a mechanism for translating between 657 SNMP versions using a third party network element. This allows 658 network elements which support only a single, but different, SNMP 659 version to communicate with each other. Proxy implementations are 660 also useful for securing communications over an insecure link between 661 two locally secure networks. 663 4.1. Multi-lingual implementations 665 This approach requires an entity to support multiple SNMP message 666 versions. Typically this means supporting SNMPv1, SNMPv2c, and 667 SNMPv3 message versions. The behaviour of various types of SNMP 668 applications which support multiple message versions is described in 669 the following sections. This approach allows entities which support 670 multiple SNMP message versions to coexist with and communicate with 671 entities which support only a single SNMP message version. 673 4.1.1. Command Generator 675 A command generator must select an appropriate message version when 676 sending requests to another entity. One way to achieve this is to 677 consult a local database to select the appropriate message version. 679 In addition, a command generator MUST 'downgrade' GetBulk requests to 680 GetNext requests when selecting SNMPv1 as the message version for an 681 outgoing request. This is done by simply changing the operation type 682 to GetNext, ignoring any non-repeaters and max-repetitions values, 683 and setting error-status and error-index to zero. 685 4.1.2. Command Responder 687 A command responder must be able to deal with both SNMPv1 and SNMPv2 688 access to MIB data. There are three aspects to dealing with this. A 689 command responder must: 691 - Deal correctly with SNMPv2 access to MIB data that returns a 692 Counter64 value while processing an SNMPv1 message, 694 - Deal correctly with SNMPv2 access to MIB data that returns one 695 of the three exception values while processing an SNMPv1 696 message, and 698 - Map SNMPv2 error codes returned from SNMPv2 access to MIB data 699 into SNMPv1 error codes when processing an SNMPv1 message. 701 Note that SNMPv1 error codes SHOULD NOT be used without any change 702 when processing SNMPv2c or SNMPv3 messages, except in the case of 703 proxy forwarding. In the case of proxy forwarding, for backwards 704 compatibility, SNMPv1 error codes may be used without any change in a 705 forwarded SNMPv2c or SNMPv3 message. 707 The following sections describe the behaviour of a command responder 708 application which supports multiple SNMP message versions, and which 709 uses some combination of SNMPv1 and SNMPv2 access to MIB data. 711 4.1.2.1. Handling Counter64 713 The SMIv2 [7] defines one new syntax that is incompatible with SMIv1. 714 This syntax is Counter64. All other syntaxes defined by SMIv2 are 715 compatible with SMIv1. 717 The impact on multi-lingual command responders is that they MUST NOT 718 ever return a variable binding containing a Counter64 value in a 719 response to a request that was received using the SNMPv1 message 720 version. 722 Multi-lingual command responders SHALL take the approach that object 723 instances whose type is Counter64 are implicitly excluded from view 724 when processing an SNMPv1 message. So: 726 - On receipt of an SNMPv1 GetRequest-PDU containing a variable 727 binding whose name field points to an object instance of type 728 Counter64, a GetResponsePDU SHALL be returned, with an error- 729 status of noSuchName and the error-index set to the variable 730 binding that caused this error. 732 - On an SNMPv1 GetNextRequest-PDU, any object instance which 733 contains a syntax of Counter64 SHALL be skipped, and the next 734 accessible object instance that does not have the syntax of 735 Counter64 SHALL be retrieved. If no such object instance 736 exists, then an error-status of noSuchName SHALL be returned, 737 and the error-index SHALL be set to the variable binding that 738 caused this error. 740 - Any SNMPv1 request which contains a variable binding with a 741 Counter64 value is ill-formed, so the foregoing rules do not 742 apply. If that error is detected, a response SHALL NOT be 743 returned, since it would contain a copy of the ill-formed 744 variable binding. Instead, the offending PDU SHALL be 745 discarded and the counter snmpInASNParseErrs SHALL be 746 incremented. 748 4.1.2.2. Mapping SNMPv2 Exceptions 750 SNMPv2 provides a feature called exceptions, which allow an SNMPv2 751 Response PDU to return as much management information as possible, 752 even when an error occurs. However, SNMPv1 does not support 753 exceptions, and so an SNMPv1 Response PDU cannot return any 754 management information, and can only return an error-status and 755 error-index value. 757 When an SNMPv1 request is received, a command responder MUST check 758 any variable bindings returned using SNMPv2 access to MIB data for 759 exception values, and convert these exception values into SNMPv1 760 error codes. 762 The type of exception that can be returned when accessing MIB data 763 and the action taken depends on the type of SNMP request. 765 - For a GetRequest, a noSuchObject or noSuchInstance exception 766 may be returned. 768 - For a GetNextRequest, an endOfMibView exception may be 769 returned. 771 - No exceptions will be returned for a SetRequest, and a 772 GetBulkRequest should only be received in an SNMPv2c or SNMPv3 773 message, so these request types may be ignored when mapping 774 exceptions. 776 Note that when a response contains multiple exceptions, it is an 777 implementation choice as to which variable binding the error-index 778 should reference. 780 4.1.2.2.1. Mapping noSuchObject and noSuchInstance 782 A noSuchObject or noSuchInstance exception generated by an SNMPv2 783 access to MIB data indicates that the requested object instance can 784 not be returned. The SNMPv1 error code for this condition is 785 noSuchName, and so the error-status field of the response PDU SHALL 786 be set to noSuchName. Also, the error-index field SHALL be set to 787 the index of the variable binding for which an exception occurred 788 (there may be more than one and it is an implementation decision as 789 to which is used), and the variable binding list from the original 790 request SHALL be returned with the response PDU. 792 4.1.2.2.2. Mapping endOfMibView 794 When an SNMPv2 access to MIB data returns a variable binding 795 containing an endOfMibView exception, it indicates that there are no 796 object instances available which lexicographically follow the object 797 in the request. In an SNMPv1 agent, this condition normally results 798 in a noSuchName error, and so the error-status field of the response 799 PDU SHALL be set to noSuchName. Also, the error-index field SHALL be 800 set to the index of the variable binding for which an exception 801 occurred (there may be more than one and it is an implementation 802 decision as to which is used), and the variable binding list from the 803 original request SHALL be returned with the response PDU. 805 4.1.2.3. Processing An SNMPv1 GetRequest 807 When processing an SNMPv1 GetRequest, the following procedures MUST 808 be followed when using an SNMPv2 access to MIB data. 810 When such an access to MIB data returns response data using SNMPv2 811 syntax and error-status values, then: 813 (1) If the error-status is anything other than noError, 815 - The error status SHALL be translated to an SNMPv1 error-status 816 using the table in section 4.3, "Error Status Mappings". 818 - The error-index SHALL be set to the position (in the original 819 request) of the variable binding that caused the error-status. 821 - The variable binding list of the response PDU SHALL be made 822 exactly the same as the variable binding list that was 823 received in the original request. 825 (2) If the error-status is noError, the variable bindings SHALL be 826 checked for any SNMPv2 exception (noSuchObject or noSuchInstance) 827 or an SNMPv2 syntax that is unknown to SNMPv1 (Counter64). If 828 there are any such variable bindings, one of those variable 829 bindings SHALL be selected (it is an implementation choice as to 830 which is selected), and: 832 - The error-status SHALL be set to noSuchName, 834 - The error-index SHALL be set to the position (in the variable 835 binding list of the original request) of the selected variable 836 binding, and 838 - The variable binding list of the response PDU SHALL be exactly 839 the same as the variable binding list that was received in the 840 original request. 842 (3) If there are no such variable bindings, then: 844 - The error-status SHALL be set to noError, 846 - The error-index SHALL be set to zero, and 848 - The variable binding list of the response SHALL be composed 849 from the data as it is returned by the access to MIB data. 851 4.1.2.4. Processing An SNMPv1 GetNextRequest 853 When processing an SNMPv1 GetNextRequest, the following procedures 854 MUST be followed when an SNMPv2 access to MIB data is called as part 855 of processing the request. There may be repetitive accesses to MIB 856 data to try to find the first object which lexicographically follows 857 each of the objects in the request. This is implementation specific. 858 These procedures are followed only for data returned when using 859 SNMPv2 access to MIB data. Data returned using SNMPv1 access to MIB 860 data may be treated in the normal manner for an SNMPv1 request. 862 First, if the access to MIB data returns an error-status of anything 863 other than noError: 865 (1) The error status SHALL be translated to an SNMPv1 error-status 866 using the table in section 4.3, "Error Status Mappings". 868 (2) The error-index SHALL be set to the position (in the original 869 request) of the variable binding that caused the error-status. 871 (3) The variable binding list of the response PDU SHALL be exactly the 872 same as the variable binding list that was received in the original 873 request. 875 Otherwise, if the access to MIB data returns an error-status of 876 noError: 878 (1) Any variable bindings containing an SNMPv2 syntax of Counter64 879 SHALL be considered to be not in view, and MIB data SHALL be 880 accessed as many times as is required until either a value other 881 than Counter64 is returned, or an error occurs. 883 (2) If there is any variable binding that contains an SNMPv2 exception 884 endOfMibView (there may be more than one, it is an implementation 885 decision as to which is chosen): 887 - The error-status SHALL be set to noSuchName, 889 - The error-index SHALL be set to the position (in the variable 890 binding list of the original request) of the variable binding 891 that returned such an SNMPv2 exception, and 893 - The variable binding list of the response PDU SHALL be exactly 894 the same as the variable binding list that was received in the 895 original request. 897 (3) If there are no such variable bindings, then: 899 - The error-status SHALL be set to noError, 901 - The error-index SHALL be set to zero, and 903 - The variable binding list of the response SHALL be composed 904 from the data as it is returned by the access to MIB data. 906 4.1.2.5. Processing An SNMPv1 SetRequest 908 When processing an SNMPv1 SetRequest, the following procedures MUST 909 be followed when calling SNMPv2 MIB access routines. 911 When such MIB access routines return response data using SNMPv2 912 syntax and error-status values, and the error-status is anything 913 other than noError, then: 915 - The error status SHALL be translated to an SNMPv1 error-status 916 using the table in section 4.3, "Error Status Mappings". 918 - The error-index SHALL be set to the position (in the original 919 request) of the variable binding that caused the error-status. 921 - The variable binding list of the response PDU SHALL be made 922 exactly the same as the variable binding list that was 923 received in the original request. 925 In addition, whenever the SNMPv2 error-status value of 926 authorizationError is translated to an SNMPv1 error-status value of 927 noSuchName, the value of snmpInBadCommunityUses MUST be incremented. 929 4.1.3. Notification Originator 931 A notification originator must be able to translate between SNMPv1 932 notifications parameters and SNMPv2 notification parameters in order 933 to send a notification using a particular SNMP message version. If a 934 notification is generated using SNMPv1 notification parameters, and 935 configuration information specifies that notifications be sent using 936 SNMPv2c or SNMPv3, the notification parameters must be translated to 937 SNMPv2 notification parameters. Likewise, if a notification is 938 generated using SNMPv2 notification parameters, and configuration 939 information specifies that notifications be sent using SNMPv1, the 940 notification parameters must be translated to SNMPv1 notification 941 parameters. In this case, if the notification cannot be translated 942 (due to the presence of a Counter64 type), it will not be sent using 943 SNMPv1. 945 When a notification originator generates a notification, using 946 parameters obtained from the SNMP-TARGET-MIB and SNMP-NOTIFICATION- 947 MIB, if the SNMP version used to generate the notification is SNMPv1, 948 the PDU type used will always be a TrapPDU, regardless of whether the 949 value of snmpNotifyType is trap(1) or inform(2). 951 Note also that access control and notification filtering are 952 performed in the usual manner for notifications, regardless of the 953 SNMP message version to be used when sending a notification. The 954 parameters for performing access control are found in the usual 955 manner (i.e., from inspecting the SNMP-TARGET-MIB and SNMP- 956 NOTIFICATION-MIB). In particular, when generating an SNMPv1 Trap, in 957 order to perform the access check specified in [18], section 3.3, 958 bullet (3), the notification originator may need to generate a value 959 for snmpTrapOID.0 as described in section 3.1, bullets (2) and (3) of 960 this document. If the SNMPv1 notification parameters being used were 961 previously translated from a set of SNMPv2 notification parameters, 962 this value may already be known, in which case it need not be 963 generated. 965 4.1.4. Notification Receiver 967 There are no special requirements of a notification receiver. 968 However, an implementation may find it useful to allow a higher level 969 application to request whether notifications should be delivered to a 970 higher level application using SNMPv1 notification parameter or 971 SNMPv2 notification parameters. The notification receiver would then 972 translate notification parameters when required in order to present a 973 notification using the desired set of parameters. 975 4.2. Proxy Implementations 977 A proxy implementation may be used to enable communication between 978 entities which support different SNMP message versions. This is 979 accomplished in a proxy forwarder application by performing 980 translations on PDUs. These translations depend on the PDU type, the 981 SNMP version of the packet containing a received PDU, and the SNMP 982 version to be used to forward a received PDU. The following sections 983 describe these translations. In all cases other than those described 984 below, the proxy SHALL forward a received PDU without change, subject 985 to size contraints as defined in section 5.3 (Community MIB) of this 986 document. Note that in the following sections, the 'Upstream 987 Version' refers to the version used between the command generator and 988 the proxy, and the 'Downstream Version' refers to the version used 989 between the proxy and the command responder. 991 4.2.1. Upstream Version Greater Than Downstream Version 993 - If a GetBulkRequest-PDU is received and must be forwarded 994 using the SNMPv1 message version, the proxy forwarder SHALL 995 set the non-repeaters and max-repetitions fields to 0, and 996 SHALL set the tag of the PDU to GetNextRequest-PDU. 998 - If a GetResponse-PDU is received whose error-status field has 999 a value of 'tooBig', the message will be forwarded using the 1000 SNMPv2c or SNMPv3 message version, and the original request 1001 received by the proxy was not a GetBulkRequest-PDU, the proxy 1002 forwarder SHALL remove the contents of the variable-bindings 1003 field before forwarding the response. 1005 - If a GetResponse-PDU is received whose error-status field has 1006 a value of 'tooBig,' and the message will be forwarded using 1007 the SNMPv2c or SNMPv3 message version, and the original 1008 request received by the proxy was a GetBulkRequest-PDU, the 1009 proxy forwarder SHALL re-send the forwarded request (which 1010 would have been altered to be a GetNextRequest-PDU) with all 1011 but the first variable-binding removed. The proxy forwarder 1012 SHALL only re-send such a request a single time. If the 1013 resulting GetResponse-PDU also contains an error-status field 1014 with a value of 'tooBig,' then the proxy forwarder SHALL 1015 remove the contents of the variable-bindings field, and change 1016 the error-status field to 'noError' before forwarding the 1017 response. Note that if the original request only contained a 1018 single variable-binding, the proxy may skip re-sending the 1019 request and simply remove the variable-bindings and change the 1020 error-status to 'noError.' 1022 - If a Trap-PDU is received, and will be forwarded using the 1023 SNMPv2c or SNMPv3 message version, the proxy SHALL apply the 1024 translation rules described in section 3, and SHALL forward 1025 the notification as an SNMPv2-Trap-PDU. 1027 Note that when an SNMPv1 agent generates a message containing 1028 a Trap-PDU which is subsequently forwarded by one or more 1029 proxy forwarders using SNMP versions other than SNMPv1, the 1030 community string and agent-addr fields from the original 1031 message generated by the SNMPv1 agent will be preserved 1032 through the use of the snmpTrapAddress and snmpTrapCommunity 1033 objects. 1035 4.2.2. Upstream Version Less Than Downstream Version 1037 - If a GetResponse-PDU is received in response to a GetRequest- 1038 PDU (previously generated by the proxy) which contains 1039 variable-bindings of type Counter64 or which contain an SNMPv2 1040 exception code, and the message would be forwarded using the 1041 SNMPv1 message version, the proxy MUST generate an alternate 1042 response PDU consisting of the request-id and variable 1043 bindings from the original SNMPv1 request, containing a 1044 noSuchName error-status value, and containing an error-index 1045 value indicating the position of the variable-binding 1046 containing the Counter64 type or exception code. 1048 - If a GetResponse-PDU is received in response to a 1049 GetNextRequest-PDU (previously generated by the proxy) which 1050 contains variable-bindings that contain an SNMPv2 exception 1051 code, and the message would be forwarded using the SNMPv1 1052 message version, the proxy MUST generate an alternate response 1053 PDU consisting of the request-id and variable bindings from 1054 the original SNMPv1 request, containing a noSuchName error- 1055 status value, and containing an error-index value indicating 1056 the position of the variable-binding containing the exception 1057 code. 1059 - If a GetResponse-PDU is received in response to a 1060 GetNextRequest-PDU (previously generated by the proxy) which 1061 contains variable-bindings of type Counter64, the proxy MUST 1062 re-send the entire GetNextRequest-PDU, with the following 1063 modifications. For any variable bindings in the received 1064 GetResponse which contained Counter64 types, the proxy 1065 substitutes the object names of these variable bindings for 1066 the corresponding object names in the previously-sent 1067 GetNextRequest. The proxy MUST repeat this process until no 1068 Counter64 objects are returned. Note that an implementation 1069 may attempt to optimize this process of skipping Counter64 1070 objects. One approach to such an optimization would be to 1071 replace the last sub-identifier of the object names of 1072 varbinds containing a Counter64 type with 65535 if that sub- 1073 identifier is less than 65535, or with 4294967295 if that 1074 sub-identifier is greater than 65535. This approach should 1075 skip multiple instances of the same Counter64 object, while 1076 maintaining compatibility with some broken agent 1077 implementations (which only use 16-bit integers for sub- 1078 identifiers). 1080 Deployment Hint: The process of repeated GetNext requests 1081 used by a proxy when Counter64 types are returned can be 1082 expensive. When deploying a proxy, this can be avoided by 1083 configuring the target agents to which the proxy forwards 1084 requests in a manner such that any objects of type Counter64 1085 are in fact not-in-view for the principal that the proxy is 1086 using when communicating with these agents. 1088 - If a GetResponse-PDU is received which contains an SNMPv2 1089 error-status value of wrongValue, wrongEncoding, wrongType, 1090 wrongLength, inconsistentValue, noAccess, notWritable, 1091 noCreation, inconsistentName, resourceUnavailable, 1092 commitFailed, undoFailed, or authorizationError, the error- 1093 status value is modified using the mappings in section 4.3. 1095 - If an SNMPv2-Trap-PDU is received, and will be forwarded using 1096 the SNMPv1 message version, the proxy SHALL apply the 1097 translation rules described in section 3, and SHALL forward 1098 the notification as a Trap-PDU. Note that if the translation 1099 fails due to the existence of a Counter64 data-type in the 1100 received SNMPv2-Trap-PDU, the trap cannot be forwarded using 1101 SNMPv1. 1103 - If an InformRequest-PDU is received, any configuration 1104 information indicating that it would be forwarded using the 1105 SNMPv1 message version SHALL be ignored. An InformRequest-PDU 1106 can only be forwarded using the SNMPv2c or SNMPv3 message 1107 version. The InformRequest-PDU may still be forwarded if 1108 there is other configuration information indicating that it 1109 should be forwarded using SNMPv2c or SNMPv3. 1111 4.3. Error Status Mappings 1113 The following tables shows the mappings of SNMPv1 error-status values 1114 into SNMPv2 error-status values, and the mappings of SNMPv2 error- 1115 status values into SNMPv1 error-status values. 1117 SNMPv1 error-status SNMPv2 error-status 1118 =================== =================== 1119 noError noError 1120 tooBig tooBig 1121 noSuchName noSuchName 1122 badValue badValue 1123 genErr genErr 1125 SNMPv2 error-status SNMPv1 error-status 1126 =================== =================== 1127 noError noError 1128 tooBig tooBig 1129 genErr genErr 1130 wrongValue badValue 1131 wrongEncoding badValue 1132 wrongType badValue 1133 wrongLength badValue 1134 inconsistentValue badValue 1135 noAccess noSuchName 1136 notWritable noSuchName 1137 noCreation noSuchName 1138 inconsistentName noSuchName 1139 resourceUnavailable genErr 1140 commitFailed genErr 1141 undoFailed genErr 1142 authorizationError noSuchName 1144 5. Message Processing Models and Security Models 1146 In order to adapt SNMPv1 (and SNMPv2c) into the SNMP architecture, 1147 the following models are defined in this document: 1149 - The SNMPv1 Message Processing Model 1151 - The SNMPv1 Community-Based Security Model 1153 The following models are also described in this document: 1155 - The SNMPv2c Message Processing Model 1157 - The SNMPv2c Community-Based Security Model 1159 In most respects, the SNMPv1 Message Processing Model and the 1160 SNMPv2c Message Processing Model are identical, and so these 1161 are not discussed independently in this document. Differences 1162 between the two models are described as required. 1164 Similarly, the SNMPv1 Community-Based Security Model and the 1165 SNMPv2c Community-Based Security Model are nearly identical, 1166 and so are not discussed independently. Differences between 1167 these two models are also described as required. 1169 5.1. Mappings 1171 The SNMPv1 (and SNMPv2c) Message Processing Model and Security Model 1172 require mappings between parameters used in SNMPv1 (and SNMPv2c) 1173 messages, and the version independent parameters used in the SNMP 1174 architecture [16]. The parameters which MUST be mapped consist of the 1175 SNMPv1 (and SNMPv2c) community name, and the SNMP securityName and 1176 contextEngineID/contextName pair. A MIB module (the SNMP-COMMUNITY-MIB) 1177 is provided in this document in order to perform these mappings. This 1178 MIB provides mappings in both directions, that is, a community name may 1179 be mapped to a securityName, contextEngineID, and contextName, or the 1180 combination of securityName, contextEngineID, and contextName may be 1181 mapped to a community name. 1183 5.2. The SNMPv1 MP Model and SNMPv1 Community-based Security Model 1185 The SNMPv1 Message Processing Model handles processing of SNMPv1 1186 messages. The processing of messages is handled generally in the 1187 same manner as described in RFC1157 [2], with differences and 1188 clarifications as described in the following sections. The 1189 SnmpMessageProcessingModel value for SNMPv1 is 0 (the value for 1190 SNMPv2c is 1). 1192 5.2.1. Processing An Incoming Request 1194 In RFC1157 [2], section 4.1, item (3) for an entity which receives a 1195 message, states that various parameters are passed to the 'desired 1196 authentication scheme.' The desired authentication scheme in this 1197 case is the SNMPv1 Community-Based Security Model, which will be 1198 called using the processIncomingMsg ASI. The parameters passed to 1199 this ASI are: 1201 - The messageProcessingModel, which will be 0 (or 1 for 1202 SNMPv2c). 1204 - The maxMessageSize, which should be the maximum size of a 1205 message that the receiving entity can generate (since there is 1206 no such value in the received message). 1208 - The securityParameters, which consist of the community string 1209 and the message's source and destination transport domains and 1210 addresses. 1212 - The securityModel, which will be 1 (or 2 for SNMPv2c). 1214 - The securityLevel, which will be noAuthNoPriv. 1216 - The wholeMsg and wholeMsgLength. 1218 The Community-Based Security Model will attempt to select a row in 1219 the snmpCommunityTable. This is done by performing a search through 1220 the snmpCommunityTable in lexicographic order. The first entry for 1221 which the following matching criteria are satisfied will be selected: 1223 - The community string is equal to the snmpCommunityName value. 1225 - If the snmpCommunityTransportTag is an empty string, it is 1226 ignored for the purpose of matching. If the 1227 snmpCommunityTransportTag is not an empty string, the 1228 transportDomain and transportAddress from which the message 1229 was received must match one of the entries in the 1230 snmpTargetAddrTable selected by the snmpCommunityTransportTag 1231 value. The snmpTargetAddrTMask object is used as described in 1232 section 5.3 when checking whether the transportDomain and 1233 transportAddress matches a entry in the snmpTargetAddrTable. 1235 If no such entry can be found, an authentication failure occurs as 1236 described in RFC1157 [2], and the snmpInBadCommunityNames counter is 1237 incremented. 1239 The parameters returned from the Community-Based Security Model are: 1241 - The securityEngineID, which will always be the local value of 1242 snmpEngineID.0. 1244 - The securityName. 1246 - The scopedPDU. Note that this parameter will actually consist 1247 of three values, the contextSnmpEngineID, the contextName, and 1248 the PDU. These must be separate values, since the first two 1249 do not actually appear in the message. 1251 - The maxSizeResponseScopedPDU. 1253 - The securityStateReference. 1255 The appropriate SNMP application will then be called (depending on 1256 the value of the contextEngineID and the request type in the PDU) 1257 using the processPdu ASI. The parameters passed to this ASI are: 1259 - The messageProcessingModel, which will be 0 (or 1 for 1260 SNMPv2c). 1262 - The securityModel, which will be 1 (or 2 for SNMPv2c). 1264 - The securityName, which was returned from the call to 1265 processIncomingMsg. 1267 - The securityLevel, which is noAuthNoPriv. 1269 - The contextEngineID, which was returned as part of the 1270 ScopedPDU from the call to processIncomingMsg. 1272 - The contextName, which was returned as part of the ScopedPDU 1273 from the call to processIncomingMsg. 1275 - The pduVersion, which should indicate an SNMPv1 version PDU 1276 (if the message version was SNMPv2c, this would be an SNMPv2 1277 version PDU). 1279 - The PDU, which was returned as part of the ScopedPDU from the 1280 call to processIncomingMsg. 1282 - The maxSizeResponseScopedPDU which was returned from the call 1283 to processIncomingMsg. 1285 - The stateReference which was returned from the call to 1286 processIncomingMsg. 1288 The SNMP application should process the request as described 1289 previously in this document. Note that access control is applied by 1290 an SNMPv3 command responder application as usual. The parameters as 1291 passed to the processPdu ASI will be used in calls to the 1292 isAccessAllowed ASI. 1294 5.2.2. Generating An Outgoing Response 1296 There is no special processing required for generating an outgoing 1297 response. However, the community string used in an outgoing response 1298 must be the same as the community string from the original request. 1299 The original community string MUST be present in the stateReference 1300 information of the original request. 1302 5.2.3. Generating An Outgoing Notification 1304 In a multi-lingual SNMP entity, the parameters used for generating 1305 notifications will be obtained by examining the SNMP-TARGET-MIB and 1306 SNMP-NOTIFICATION-MIB. These parameters will be passed to the SNMPv1 1307 Message Processing Model using the sendPdu ASI. The SNMPv1 Message 1308 Processing Model will attempt to locate an appropriate community 1309 string in the snmpCommunityTable based on the parameters passed to 1310 the sendPdu ASI. This is done by performing a search through the 1311 snmpCommunityTable in lexicographic order. The first entry for which 1312 the following matching criteria are satisfied will be selected: 1314 - The securityName must be equal to the 1315 snmpCommunitySecurityName value. 1317 - The contextEngineID must be equal to the 1318 snmpCommunityContextEngineID value. 1320 - The contextName must be equal to the snmpCommunityContextName 1321 value. 1323 - If the snmpCommunityTransportTag is an empty string, it is 1324 ignored for the purpose of matching. If the 1325 snmpCommunityTransportTag is not an empty string, the 1326 transportDomain and transportAddress must match one of the 1327 entries in the snmpTargetAddrTable selected by the 1328 snmpCommunityTransportTag value. 1330 If no such entry can be found, the notification is not sent. 1331 Otherwise, the community string used in the outgoing notification 1332 will be the value of the snmpCommunityName column of the selected 1333 row. 1335 5.3. The SNMP Community MIB Module 1337 The SNMP-COMMUNITY-MIB contains objects for mapping between community 1338 strings and version-independent SNMP message parameters. In 1339 addition, this MIB provides a mechanism for performing source address 1340 validation on incoming requests, and for selecting community strings 1341 based on target addresses for outgoing notifications. These two 1342 features are accomplished by providing a tag in the 1343 snmpCommunityTable which selects sets of entries in the 1344 snmpTargetAddrTable [18]. In addition, the SNMP-COMMUNITY-MIB 1345 augments the snmpTargetAddrTable with a transport address mask value 1346 and a maximum message size value. These values are used only where 1347 explicitly stated. In cases where the snmpTargetAddrTable is used 1348 without mention of these augmenting values, the augmenting values 1349 should be ignored. 1351 The mask value, snmpTargetAddrTMask, allows selected entries in the 1352 snmpTargetAddrTable to specify multiple addresses (rather than just a 1353 single address per entry). This would typically be used to specify a 1354 subnet in an snmpTargetAddrTable rather than just a single address. 1355 The mask value is used to select which bits of a transport address 1356 must match bits of the corresponding instance of 1357 snmpTargetAddrTAddress, in order for the transport address to match a 1358 particular entry in the snmpTargetAddrTable. The value of an 1359 instance of snmpTargetAddrTMask must always be an OCTET STRING whose 1360 length is either zero or the same as that of the corresponding 1361 instance of snmpTargetAddrTAddress. 1363 When checking whether a transport address matches an entry in the 1364 snmpTargetAddrTable, if the value of snmpTargetAddrTMask is a zero- 1365 length OCTET STRING, the mask value is ignored, and the value of 1366 snmpTargetAddrTAddress must exactly match a transport address. 1367 Otherwise, each bit of each octet in the snmpTargetAddrTMask value 1368 corresponds to the same bit of the same octet in the 1369 snmpTargetAddrTAddress value. For bits that are set in the 1370 snmpTargetAddrTMask value (i.e., bits equal to 1), the corresponding 1371 bits in the snmpTargetAddrTAddress value must match the bits in a 1372 transport address. If all such bits match, the transport address is 1373 matched by that snmpTargetAddrTable entry. Otherwise, the transport 1374 address is not matched. 1376 The maximum message size value, snmpTargetAddrMMS, is used to 1377 determine the maximum message size acceptable to another SNMP entity 1378 when the value cannot be determined from the protocol. 1380 SNMP-COMMUNITY-MIB DEFINITIONS ::= BEGIN 1382 IMPORTS 1383 IpAddress, 1384 MODULE-IDENTITY, 1385 OBJECT-TYPE, 1386 Integer32, 1387 snmpModules 1388 FROM SNMPv2-SMI 1389 RowStatus, 1390 StorageType 1391 FROM SNMPv2-TC 1392 SnmpAdminString, 1393 SnmpEngineID 1394 FROM SNMP-FRAMEWORK-MIB 1395 SnmpTagValue, 1396 snmpTargetAddrEntry 1397 FROM SNMP-TARGET-MIB 1398 MODULE-COMPLIANCE, 1399 OBJECT-GROUP 1400 FROM SNMPv2-CONF; 1402 snmpCommunityMIB MODULE-IDENTITY 1403 LAST-UPDATED "199910050000Z" -- 5 Oct 1999, midnight 1404 ORGANIZATION "SNMPv3 Working Group" 1405 CONTACT-INFO "WG-email: snmpv3@lists.tislabs.com 1406 Subscribe: majordomo@lists.tislabs.com 1407 In msg body: subscribe snmpv3 1409 Chair: Russ Mundy 1410 TIS Labs at Network Associates 1411 Postal: 3060 Washington Rd 1412 Glenwood MD 21738 1413 USA 1414 Email: mundy@tislabs.com 1415 Phone: +1-301-854-6889 1416 Co-editor: Rob Frye 1417 MCI WorldCom 1418 Postal: 2100 Reston Parkway, Suite 600 1419 Reston, VA 20191 1420 USA 1421 E-mail: Rob.Frye@wcom.com 1422 Phone: +1 703 715 7225 1424 Co-editor: David B. Levi 1425 Nortel Networks 1426 Postal: 3505 Kesterwood Drive 1427 Knoxville, TN 37918 1428 E-mail: dlevi@nortelnetworks.com 1429 Phone: +1 423 686 0432 1431 Co-editor: Shawn A. Routhier 1432 Integrated Systems Inc. 1433 Postal: 333 North Ave 4th Floor 1434 Wakefield, MA 01880 1435 E-mail: sar@epilogue.com 1436 Phone: +1 781 245 0804 1438 Co-editor: Bert Wijnen 1439 IBM T. J. Watson Research 1440 Postal: Schagen 33 1441 3461 GL Linschoten 1442 Netherlands 1443 Email: wijnen@vnet.ibm.com 1444 Phone: +31-348-432-794 1445 " 1447 DESCRIPTION 1448 "This MIB module defines objects to help support coexistence 1449 between SNMPv1, SNMPv2c, and SNMPv3." 1450 REVISION "199905130000Z" -- 13 May 1999 1451 DESCRIPTION "The Initial Revision" 1452 REVISION "199910050000Z" -- 5 Oct 1999 (same as LAST-UPDATED) 1453 DESCRIPTION "This version published as RFC xxxx" 1454 -- RFC-editor assigns xxxx 1455 ::= { snmpModules 18 } 1457 -- Administrative assignments **************************************** 1459 snmpCommunityMIBObjects OBJECT IDENTIFIER ::= { snmpCommunityMIB 1 } 1460 snmpCommunityMIBConformance OBJECT IDENTIFIER ::= { snmpCommunityMIB 2 } 1462 -- 1463 -- The snmpCommunityTable contains a database of community strings. 1464 -- This table provides mappings between community strings, and the 1465 -- parameters required for View-based Access Control. 1466 -- 1468 snmpCommunityTable OBJECT-TYPE 1469 SYNTAX SEQUENCE OF SnmpCommunityEntry 1470 MAX-ACCESS not-accessible 1471 STATUS current 1472 DESCRIPTION 1473 "The table of community strings configured in the SNMP 1474 engine's Local Configuration Datastore (LCD)." 1475 ::= { snmpCommunityMIBObjects 1 } 1477 snmpCommunityEntry OBJECT-TYPE 1478 SYNTAX SnmpCommunityEntry 1479 MAX-ACCESS not-accessible 1480 STATUS current 1481 DESCRIPTION 1482 "Information about a particular community string." 1483 INDEX { IMPLIED snmpCommunityIndex } 1484 ::= { snmpCommunityTable 1 } 1486 SnmpCommunityEntry ::= SEQUENCE { 1487 snmpCommunityIndex SnmpAdminString, 1488 snmpCommunityName OCTET STRING, 1489 snmpCommunitySecurityName SnmpAdminString, 1490 snmpCommunityContextEngineID SnmpEngineID, 1491 snmpCommunityContextName SnmpAdminString, 1492 snmpCommunityTransportTag SnmpTagValue, 1493 snmpCommunityStorageType StorageType, 1494 snmpCommunityStatus RowStatus 1495 } 1497 snmpCommunityIndex OBJECT-TYPE 1498 SYNTAX SnmpAdminString (SIZE(1..32)) 1499 MAX-ACCESS not-accessible 1500 STATUS current 1501 DESCRIPTION 1502 "The unique index value of a row in this table." 1503 ::= { snmpCommunityEntry 1 } 1505 snmpCommunityName OBJECT-TYPE 1506 SYNTAX OCTET STRING 1507 MAX-ACCESS read-create 1508 STATUS current 1509 DESCRIPTION 1510 "The community string for which a row in this table 1511 represents a configuration." 1512 ::= { snmpCommunityEntry 2 } 1514 snmpCommunitySecurityName OBJECT-TYPE 1515 SYNTAX SnmpAdminString (SIZE(1..32)) 1516 MAX-ACCESS read-create 1517 STATUS current 1518 DESCRIPTION 1519 "A human readable string representing the corresponding 1520 value of snmpCommunityName in a Security Model 1521 independent format." 1522 ::= { snmpCommunityEntry 3 } 1524 snmpCommunityContextEngineID OBJECT-TYPE 1525 SYNTAX SnmpEngineID 1526 MAX-ACCESS read-create 1527 STATUS current 1528 DESCRIPTION 1529 "The contextEngineID indicating the location of the 1530 context in which management information is accessed 1531 when using the community string specified by the 1532 corresponding instance of snmpCommunityName. 1534 The default value is the snmpEngineID of the entity in 1535 which this object is instantiated." 1536 ::= { snmpCommunityEntry 4 } 1538 snmpCommunityContextName OBJECT-TYPE 1539 SYNTAX SnmpAdminString (SIZE(0..32)) 1540 MAX-ACCESS read-create 1541 STATUS current 1542 DESCRIPTION 1543 "The context in which management information is accessed 1544 when using the community string specified by the corresponding 1545 instance of snmpCommunityName." 1546 DEFVAL { ''H } -- the empty string 1547 ::= { snmpCommunityEntry 5 } 1549 snmpCommunityTransportTag OBJECT-TYPE 1550 SYNTAX SnmpTagValue 1551 MAX-ACCESS read-create 1552 STATUS current 1553 DESCRIPTION 1554 "This object specifies a set of transport endpoints 1555 from which a command responder application will accept 1556 management requests. If a management request containing 1557 this community is received on a transport endpoint other 1558 than the transport endpoints identified by this object, 1559 the request is deemed unauthentic. 1561 The transports identified by this object are specified 1562 in the snmpTargetAddrTable. Entries in that table 1563 whose snmpTargetAddrTagList contains this tag value 1564 are identified. 1566 If the value of this object has zero-length, transport 1567 endpoints are not checked when authenticating messages 1568 containing this community string." 1569 DEFVAL { ''H } -- the empty string 1570 ::= { snmpCommunityEntry 6 } 1572 snmpCommunityStorageType OBJECT-TYPE 1573 SYNTAX StorageType 1574 MAX-ACCESS read-create 1575 STATUS current 1576 DESCRIPTION 1577 "The storage type for this conceptual row in the 1578 snmpCommunityTable. Conceptual rows having the value 1579 'permanent' need not allow write-access to any 1580 columnar object in the row." 1581 ::= { snmpCommunityEntry 7 } 1583 snmpCommunityStatus OBJECT-TYPE 1584 SYNTAX RowStatus 1585 MAX-ACCESS read-create 1586 STATUS current 1587 DESCRIPTION 1588 "The status of this conceptual row in the snmpCommunityTable. 1590 An entry in this table is not qualified for activation 1591 until instances of all corresponding columns have been 1592 initialized, either through default values, or through 1593 Set operations. The snmpCommunityName and 1594 snmpCommunitySecurityName objects must be explicitly set. 1596 There is no restriction on setting columns in this table 1597 when the value of snmpCommunityStatus is active(1)." 1598 ::= { snmpCommunityEntry 8 } 1600 -- 1601 -- The snmpTargetAddrExtTable 1602 -- 1603 snmpTargetAddrExtTable OBJECT-TYPE 1604 SYNTAX SEQUENCE OF SnmpTargetAddrExtEntry 1605 MAX-ACCESS not-accessible 1606 STATUS current 1607 DESCRIPTION 1608 "The table of mask and mms values associated with the 1609 snmpTargetAddrTable. 1611 The snmpTargetAddrExtTable augments the 1612 snmpTargetAddrTable with a transport address mask value 1613 and a maximum message size value. The transport address 1614 mask allows entries in the snmpTargetAddrTable to define 1615 a set of addresses instead of just a single address. 1616 The maximum message size value allows the maximum 1617 message size of another SNMP entity to be configured for 1618 use in SNMPv1 (and SNMPv2c) transactions, where the 1619 message format does not specify a maximum message size." 1620 ::= { snmpCommunityMIBObjects 2 } 1622 snmpTargetAddrExtEntry OBJECT-TYPE 1623 SYNTAX SnmpTargetAddrExtEntry 1624 MAX-ACCESS not-accessible 1625 STATUS current 1626 DESCRIPTION 1627 "Information about a particular mask and mms value." 1628 AUGMENTS { snmpTargetAddrEntry } 1629 ::= { snmpTargetAddrExtTable 1 } 1631 SnmpTargetAddrExtEntry ::= SEQUENCE { 1632 snmpTargetAddrTMask OCTET STRING, 1633 snmpTargetAddrMMS Integer32 1634 } 1636 snmpTargetAddrTMask OBJECT-TYPE 1637 SYNTAX OCTET STRING (SIZE (0..255)) 1638 MAX-ACCESS read-create 1639 STATUS current 1640 DESCRIPTION 1641 "The mask value associated with an entry in the 1642 snmpTargetAddrTable. The value of this object must 1643 have the same length as the corresponding instance of 1644 snmpTargetAddrTAddress, or must have length 0. An 1645 attempt to set it to any other value will result in 1646 an inconsistentValue error. 1648 The value of this object allows an entry in the 1649 snmpTargetAddrTable to specify multiple addresses. 1651 The mask value is used to select which bits of 1652 a transport address must match bits of the corresponding 1653 instance of snmpTargetAddrTAddress, in order for the 1654 transport address to match a particular entry in the 1655 snmpTargetAddrTable. Bits which are 1 in the mask 1656 value indicate bits in the transport address which 1657 must match bits in the snmpTargetAddrTAddress value. 1658 Bits which are 0 in the mask indicate bits in the 1659 transport address which need not match. If the 1660 length of the mask is 0, the mask should be treated 1661 as if all its bits were 1 and its length were equal 1662 to the length of the corresponding value of 1663 snmpTargetAddrTable. 1665 This object may not be modified while the value of the 1666 corresponding instance of snmpTargetAddrRowStatus is 1667 active(1). An attempt to set this object in this case 1668 will result in an inconsistentValue error." 1669 DEFVAL { ''H } 1670 ::= { snmpTargetAddrExtEntry 1 } 1672 snmpTargetAddrMMS OBJECT-TYPE 1673 SYNTAX Integer32 (0|484..2147483647) 1674 MAX-ACCESS read-create 1675 STATUS current 1676 DESCRIPTION 1677 "The maximum message size value associated with an entry 1678 in the snmpTargetAddrTable." 1679 DEFVAL { 484 } 1680 ::= { snmpTargetAddrExtEntry 2 } 1682 -- 1683 -- The snmpTrapAddress and snmpTrapCommunity objects are included 1684 -- in notifications that are forwarded by a proxy, which were 1685 -- originally received as SNMPv1 Trap messages. 1686 -- 1688 snmpTrapAddress OBJECT-TYPE 1689 SYNTAX IpAddress 1690 MAX-ACCESS accessible-for-notify 1691 STATUS current 1692 DESCRIPTION 1693 "The value of the agent-addr field of a Trap PDU which 1694 is forwarded by a proxy forwarder application using 1695 an SNMP version other than SNMPv1. The value of this 1696 object SHOULD contain the value of the agent-addr field 1697 from the original Trap PDU as generated by an SNMPv1 1698 agent." 1699 ::= { snmpCommunityMIBObjects 3 } 1701 snmpTrapCommunity OBJECT-TYPE 1702 SYNTAX OCTET STRING 1703 MAX-ACCESS accessible-for-notify 1704 STATUS current 1705 DESCRIPTION 1706 "The value of the community string field of an SNMPv1 1707 message containing a Trap PDU which is forwarded by a 1708 a proxy forwarder application using an SNMP version 1709 other than SNMPv1. The value of this object SHOULD 1710 contain the value of the community string field from 1711 the original SNMPv1 message containing a Trap PDU as 1712 generated by an SNMPv1 agent." 1713 ::= { snmpCommunityMIBObjects 4 } 1715 -- Conformance Information ******************************************* 1717 snmpCommunityMIBCompliances OBJECT IDENTIFIER 1718 ::= { snmpCommunityMIBConformance 1 } 1719 snmpCommunityMIBGroups OBJECT IDENTIFIER 1720 ::= { snmpCommunityMIBConformance 2 } 1722 -- Compliance statements 1724 snmpCommunityMIBCompliance MODULE-COMPLIANCE 1725 STATUS current 1726 DESCRIPTION 1727 "The compliance statement for SNMP engines which 1728 implement the SNMP-COMMUNITY-MIB." 1730 MODULE -- this module 1731 MANDATORY-GROUPS { snmpCommunityGroup } 1733 OBJECT snmpCommunityName 1734 MIN-ACCESS read-only 1735 DESCRIPTION "Write access is not required." 1737 OBJECT snmpCommunitySecurityName 1738 MIN-ACCESS read-only 1739 DESCRIPTION "Write access is not required." 1741 OBJECT snmpCommunityContextEngineID 1742 MIN-ACCESS read-only 1743 DESCRIPTION "Write access is not required." 1744 OBJECT snmpCommunityContextName 1745 MIN-ACCESS read-only 1746 DESCRIPTION "Write access is not required." 1748 OBJECT snmpCommunityTransportTag 1749 MIN-ACCESS read-only 1750 DESCRIPTION "Write access is not required." 1752 OBJECT snmpCommunityStorageType 1753 MIN-ACCESS read-only 1754 DESCRIPTION "Write access is not required." 1756 OBJECT snmpCommunityStatus 1757 MIN-ACCESS read-only 1758 DESCRIPTION "Write access is not required." 1760 ::= { snmpCommunityMIBCompliances 1 } 1762 snmpProxyTrapForwardCompliance MODULE-COMPLIANCE 1763 STATUS current 1764 DESCRIPTION 1765 "The compliance statement for SNMP engines which 1766 contain a proxy forwarding application which is 1767 capable of forwarding SNMPv1 traps using SNMPv2c 1768 or SNMPv3." 1769 MODULE -- this module 1770 MANDATORY-GROUPS { snmpProxyTrapForwardGroup } 1771 ::= { snmpCommunityMIBCompliances 2 } 1773 snmpCommunityGroup OBJECT-GROUP 1774 OBJECTS { 1775 snmpCommunityName, 1776 snmpCommunitySecurityName, 1777 snmpCommunityContextEngineID, 1778 snmpCommunityContextName, 1779 snmpCommunityTransportTag, 1780 snmpCommunityStorageType, 1781 snmpCommunityStatus, 1782 snmpTargetAddrTMask, 1783 snmpTargetAddrMMS 1784 } 1785 STATUS current 1786 DESCRIPTION 1787 "A collection of objects providing for configuration 1788 of community strings for SNMPv1 (and SNMPv2c) usage." 1789 ::= { snmpCommunityMIBGroups 1 } 1791 snmpProxyTrapForwardGroup OBJECT-GROUP 1792 OBJECTS { 1793 snmpTrapAddress, 1794 snmpTrapCommunity 1795 } 1796 STATUS current 1797 DESCRIPTION 1798 "Objects which are used by proxy forwarding applications 1799 when translating traps between SNMP versions. These are 1800 used to preserve SNMPv1-specific information when 1801 translating to SNMPv2c or SNMPv3." 1802 ::= { snmpCommunityMIBGroups 3 } 1804 END 1806 6. Intellectual Property 1808 The IETF takes no position regarding the validity or scope of any 1809 intellectual property or other rights that might be claimed to 1810 pertain to the implementation or use of the technology described in 1811 this document or the extent to which any license under such rights 1812 might or might not be available; neither does it represent that it 1813 has made any effort to identify any such rights. Information on the 1814 IETF's procedures with respect to rights in standards-track and 1815 standards-related documentation can be found in BCP-11. Copies of 1816 claims of rights made available for publication and any assurances of 1817 licenses to be made available, or the result of an attempt made to 1818 obtain a general license or permission for the use of such 1819 proprietary rights by implementors or users of this specification can 1820 be obtained from the IETF Secretariat. 1822 The IETF invites any interested party to bring to its attention any 1823 copyrights, patents or patent applications, or other proprietary 1824 rights which may cover technology that may be required to practice 1825 this standard. Please address the information to the IETF Executive 1826 Director. 1828 7. Acknowledgments 1830 This document is the result of the efforts of the SNMPv3 Working 1831 Group. The design of the SNMP-COMMUNITY-MIB incorporates work done 1832 by the authors of SNMPv2*: 1834 Jeff Case (SNMP Research, Inc.) 1835 David Harrington (Cabletron Systems Inc.) 1836 David Levi (SNMP Research, Inc.) 1837 Brian O'Keefe (Hewlett Packard) 1838 Jon Saperia (IronBridge Networks, Inc.) 1839 Steve Waldbusser (International Network Services) 1841 8. Security Considerations 1843 Although SNMPv1 and SNMPv2 do not provide any security, allowing 1844 community names to be mapped into securityName/contextName provides 1845 the ability to use view-based access control to limit the access of 1846 unsecured SNMPv1 and SNMPv2 operations. In fact, it is important for 1847 network administrators to make use of this capability in order to 1848 avoid unauthorized access to MIB data that would otherwise be secure. 1850 Further, the SNMP-COMMUNITY-MIB has the potential to expose community 1851 strings which provide access to more information than that which is 1852 available using the usual 'public' community string. For this 1853 reason, a security administrator may wish to limit accessibility to 1854 the SNMP-COMMUNITY-MIB, and in particular, to make it inaccessible 1855 when using the 'public' community string. 1857 When a proxy implementation translates messages between SNMPv1 (or 1858 SNMPv2c) and SNMPv3, there may be a loss of security. For example, 1859 an SNMPv3 message received using authentication and privacy which is 1860 subsequently forwarded using SNMPv1 will lose the security benefits 1861 of using authentication and privacy. Careful configuration of 1862 proxies is required to address such situations. One approach to deal 1863 with such situations might be to use an encrypted tunnel. 1865 9. References 1867 [1] Rose, M. and K. McCloghrie, "Structure and Identification of 1868 Management Information for TCP/IP-based internets"", STD16, RFC 1869 1155, May 1990. 1871 [2] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Network 1872 Management Protocol", STD15, RFC 1157, SNMP Research, Performance 1873 Systems International, Performance Systems International, MIT 1874 Laboratory for Computer Science, May 1990. 1876 [3] McCloghrie, K., and M. Rose, Editors, "Concise MIB Definitions", 1877 STD 16, RFC 1212, Hughes LAN Systems, Performance Systems 1878 International, March 1991. 1880 [4] Rose, M. T., "A Convention for Defining Traps for use with the 1881 SNMP", RFC 1215, March 1991. 1883 [5] McCloghrie, K., and M. Rose, "A Convention for Describing SNMP- 1884 based Agents", RFC 1303, Hughes LAN Systems, Dover Beach 1885 Consulting, Inc., February 1992. 1887 [6] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. 1888 Waldbusser, "Introduction to Community-based SNMPv2", RFC1901, SNMP 1889 Research,Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., 1890 International Network Services, January 1996. 1892 [7] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., 1893 and S. Waldbusser, "Structure of Management Information Version 2 1894 (SMIv2)", RFC 2578, STD 58, Cisco Systems, SNMPinfo, TU 1895 Braunschweig, SNMP Research, First Virtual Holdings, International 1896 Network Services, April 1999. 1898 [8] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., 1899 and S. Waldbusser, "Textual Conventions for SMIv2", RFC 2579, STD 1900 58, Cisco Systems, SNMPinfo, TU Braunschweig, SNMP Research, First 1901 Virtual Holdings, International Network Services, April 1999. 1903 [9] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., 1904 and S. Waldbusser, "Conformance Statements for SMIv2", RFC 2580, 1905 STD 58, Cisco Systems, SNMPinfo, TU Braunschweig, SNMP Research, 1906 First Virtual Holdings, International Network Services, April 1999. 1908 [10] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. 1909 Waldbusser, "Protocol Operations for Version 2 of the Simple 1910 Network Management Protocol (SNMPv2)", RFC1905, SNMP Research,Inc., 1911 Cisco Systems, Inc., Dover Beach Consulting, Inc., International 1912 Network Services, January 1996. 1914 [11] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport 1915 Mappings for Version 2 of the Simple Network Management Protocol 1916 (SNMPv2)", RFC 1906, January 1996. 1918 [12] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. 1919 Waldbusser, "Management Information Base for Version 2 of the 1920 Simple Network Management Protocol (SNMPv2)", RFC1907, SNMP 1921 Research,Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., 1922 International Network Services, January 1996. 1924 [13] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. 1925 Waldbusser, "Coexistence between Version 1 and Version 2 of the 1926 Internet-standard Network Management Framework", RFC1908, SNMP 1927 Research,Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., 1928 International Network Services, January 1996. 1930 [14] Levi, D., Wijnen, B., "Mapping SNMPv2 onto SNMPv1 within a bi- 1931 lingual SNMP agent", RFC2089, SNMP Research, Inc., IBM, January 1932 1997. 1934 [15] Bradner, S., "Key words for use in RFCs to Indicate Requirement 1935 Levels", BCP 14, RFC 2119, March 1997. 1937 [16] The SNMPv3 Working Group, Harrington, D., Wijnen, B., "An 1938 Architecture for Describing SNMP Management Frameworks", RFC 2571, 1939 May 1999. 1941 [17] The SNMPv3 Working Group, Case, J., Harrington, D., Wijnen, B., 1942 "Message Processing and Dispatching for the Simple Network 1943 Management Protocol (SNMP)", RFC 2572, May 1999. 1945 [18] The SNMPv3 Working Group, Levi, D., Meyer, P., Stewart, B., "SNMP 1946 Applications", RFC2573, May 1999. 1948 [19] The SNMPv3 Working Group, Blumenthal, U., Wijnen, B., "The User- 1949 Based Security Model for Version 3 of the Simple Network Management 1950 Protocol (SNMP)", RFC 2574, May 1999. 1952 [20] The SNMPv3 Working Group, Wijnen, B., Presuhn, R., McCloghrie, K., 1953 "View-based Access Control Model for the Simple Network Management 1954 Protocol (SNMP)", RFC 2575, May 1999. 1956 10. Editor's Address 1958 Rob Frye 1959 MCI WorldCom 1960 2100 Reston Parkway, Suite 600 1961 Reston, VA 20191 1962 U.S.A. 1963 Phone: +1 703 715 7225 1964 EMail: Rob.Frye@wcom.com 1966 David B. Levi 1967 Nortel Networks 1968 3505 Kesterwood Drive 1969 Knoxville, TN 37918 1970 U.S.A. 1971 Phone: +1 423 686 0432 1972 EMail: dlevi@nortelnetworks.com 1974 Shawn A. Routhier 1975 Integrated Systems Inc. 1976 333 North Ave 4th Floor 1977 Wakefield MA 01880 1978 U.S.A. 1979 Phone: + 1 781 245 0804 1980 EMail: sar@epilogue.com 1982 Bert Wijnen 1983 IBM T. J. Watson Research 1984 Schagen 33 1985 3461 GL Linschoten 1986 Netherlands 1987 Phone: +31 348 432 794 1988 EMail: wijnen@vnet.ibm.com 1990 A. 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