idnits 2.17.1 draft-ietf-radext-rfc3576bis-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** It looks like you're using RFC 3978 boilerplate. You should update this to the boilerplate described in the IETF Trust License Policy document (see https://trustee.ietf.org/license-info), which is required now. -- Found old boilerplate from RFC 3978, Section 5.1 on line 17. -- Found old boilerplate from RFC 3978, Section 5.5, updated by RFC 4748 on line 1569. -- Found old boilerplate from RFC 3979, Section 5, paragraph 1 on line 1546. -- Found old boilerplate from RFC 3979, Section 5, paragraph 2 on line 1553. -- Found old boilerplate from RFC 3979, Section 5, paragraph 3 on line 1559. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- -- The draft header indicates that this document obsoletes RFC3576, but the abstract doesn't seem to mention this, which it should. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust Copyright Line does not match the current year == The document seems to use 'NOT RECOMMENDED' as an RFC 2119 keyword, but does not include the phrase in its RFC 2119 key words list. -- The exact meaning of the all-uppercase expression 'MAY NOT' is not defined in RFC 2119. If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: Where RADIUS is run over IPsec ESP with a non-null transform, the secret shared between the NAS and the RADIUS server MAY NOT be configured. In this case, a shared secret of zero length MUST be assumed. However, a RADIUS server that cannot know whether incoming traffic is IPsec-protected MUST be configured with a non-null RADIUS shared secret. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- Couldn't find a document date in the document -- date freshness check skipped. -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'Note 1' is mentioned on line 890, but not defined == Missing Reference: 'Note 6' is mentioned on line 921, but not defined == Missing Reference: 'Note 3' is mentioned on line 904, but not defined == Missing Reference: 'Note 2' is mentioned on line 896, but not defined == Missing Reference: 'Note 7' is mentioned on line 948, but not defined == Missing Reference: 'Note 5' is mentioned on line 916, but not defined == Missing Reference: 'Note 8' is mentioned on line 967, but not defined == Missing Reference: 'Note 4' is mentioned on line 910, but not defined ** Obsolete normative reference: RFC 2401 (Obsoleted by RFC 4301) ** Obsolete normative reference: RFC 2406 (Obsoleted by RFC 4303, RFC 4305) ** Obsolete normative reference: RFC 2409 (Obsoleted by RFC 4306) ** Obsolete normative reference: RFC 3280 (Obsoleted by RFC 5280) ** Obsolete normative reference: RFC 4282 (Obsoleted by RFC 7542) -- Obsolete informational reference (is this intentional?): RFC 3588 (Obsoleted by RFC 6733) -- Obsolete informational reference (is this intentional?): RFC 3576 (Obsoleted by RFC 5176) -- Obsolete informational reference (is this intentional?): RFC 4005 (Obsoleted by RFC 7155) -- Obsolete informational reference (is this intentional?): RFC 4330 (Obsoleted by RFC 5905) Summary: 6 errors (**), 0 flaws (~~), 11 warnings (==), 14 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Murtaza S. Chiba 3 INTERNET-DRAFT Gopal Dommety 4 Obsoletes: 3576 Mark Eklund 5 Category: Informational Cisco Systems, Inc. 6 David Mitton 7 19 January 2007 RSA Security, Inc. 8 Bernard Aboba 9 Microsoft Corporation 11 Dynamic Authorization Extensions to Remote Authentication Dial In User 12 Service (RADIUS) 14 By submitting this Internet-Draft, each author represents that any 15 applicable patent or other IPR claims of which he or she is aware 16 have been or will be disclosed, and any of which he or she becomes 17 aware will be disclosed, in accordance with Section 6 of BCP 79. 19 Internet-Drafts are working documents of the Internet Engineering 20 Task Force (IETF), its areas, and its working groups. Note that 21 other groups may also distribute working documents as Internet- 22 Drafts. 24 Internet-Drafts are draft documents valid for a maximum of six months 25 and may be updated, replaced, or obsoleted by other documents at any 26 time. It is inappropriate to use Internet-Drafts as reference 27 material or to cite them other than as "work in progress." 29 The list of current Internet-Drafts can be accessed at 30 http://www.ietf.org/ietf/1id-abstracts.txt. 32 The list of Internet-Draft Shadow Directories can be accessed at 33 http://www.ietf.org/shadow.html. 35 This Internet-Draft will expire on July 20, 2007. 37 Copyright Notice 39 Copyright (C) The IETF Trust (2007). All Rights Reserved. 41 Abstract 43 This document describes a currently deployed extension to the Remote 44 Authentication Dial In User Service (RADIUS) protocol, allowing 45 dynamic changes to a user session, as implemented by network access 46 server products. This includes support for disconnecting users and 47 changing authorizations applicable to a user session. 49 Table of Contents 51 1. Introduction .......................................... 3 52 1.1 Applicability ................................... 3 53 1.2 Requirements Language ........................... 4 54 1.3 Terminology ..................................... 4 55 2. Overview ............................................. 5 56 2.1 Disconnect Messages (DM) ........................ 5 57 2.2 Change-of-Authorization Messages (CoA) .......... 5 58 2.3 Packet Format ................................... 6 59 3. Attributes ............................................ 10 60 3.1 State ........................................... 12 61 3.2 Message-Authenticator ........................... 13 62 3.3 Nonce ........................................... 14 63 3.4 Error-Cause ..................................... 14 64 3.5 Table of Attributes ............................. 17 65 4. Diameter Considerations ............................... 21 66 5. IANA Considerations ................................... 24 67 6. Security Considerations ............................... 25 68 6.1 Authorization Issues ............................ 25 69 6.2 Impersonation ................................... 25 70 6.3 IPsec Usage Guidelines .......................... 26 71 6.4 Replay Protection ............................... 29 72 7. Example Traces ........................................ 29 73 8. References ............................................ 30 74 8.1 Normative References ............................ 30 75 8.2 Informative References .......................... 31 76 ACKNOWLEDGMENTS .............................................. 31 77 AUTHORS' ADDRESSES ........................................... 32 78 Appendix A - Changes from RFC 3576 ........................... 33 79 Intellectual Property Statement .............................. 34 80 Disclaimer of Validity ....................................... 34 81 Copyright Statement .......................................... 34 82 1. Introduction 84 The RADIUS protocol, defined in [RFC2865], does not support 85 unsolicited messages sent from the RADIUS server to the Network 86 Access Server (NAS). 88 However, there are many instances in which it is desirable for 89 changes to be made to session characteristics, without requiring the 90 NAS to initiate the exchange. For example, it may be desirable for 91 administrators to be able to terminate a user session in progress. 92 Alternatively, if the user changes authorization level, this may 93 require that authorization attributes be added/deleted from a user 94 session. 96 To overcome these limitations, several vendors have implemented 97 additional RADIUS commands in order to be able to support unsolicited 98 messages sent from the RADIUS server to the NAS. These extended 99 commands provide support for Disconnect and Change-of-Authorization 100 (CoA) packets. Disconnect packets cause a user session to be 101 terminated immediately, whereas CoA packets modify session 102 authorization attributes such as data filters. 104 1.1. Applicability 106 This protocol is being recommended for publication as an 107 Informational RFC rather than as a standards-track RFC because of 108 problems that cannot be fixed without creating incompatibilities with 109 deployed implementations. This includes security vulnerabilities, as 110 well as semantic ambiguities resulting from the design of the Change- 111 of-Authorization (CoA) commands. While fixes are recommended, they 112 cannot be made mandatory since this would be incompatible with 113 existing implementations. 115 Existing implementations of this protocol do not support 116 authorization checks, so that an ISP sharing a NAS with another ISP 117 could disconnect or change authorizations for another ISP's users. 118 In order to remedy this problem, a "Reverse Path Forwarding" check is 119 recommended. See Section 6.1. for details. 121 Existing implementations utilize per-packet authentication and 122 integrity protection algorithms with known weaknesses [MD5Attack]. 123 To provide stronger per-packet authentication and integrity 124 protection, the use of IPsec is recommended. See Section 6.3 for 125 details. 127 Existing implementations lack replay protection. In order to support 128 replay detection, it is recommended that a Nonce or Event-Timestamp 129 Attribute be added to all packets in situations where IPsec replay 130 protection is not employed. See Section 6.4 for details. 132 The approach taken with CoA commands in existing implementations 133 results in a semantic ambiguity. Existing implementations of the 134 CoA-Request identify the affected session, as well as supply the 135 authorization changes. Since RADIUS Attributes included within 136 existing implementations of the CoA-Request can be used for session 137 identification or authorization change, it may not be clear which 138 function a given attribute is serving. 140 The problem does not exist within the Diameter protocol [RFC3588], in 141 which server-initiated authorization change is initiated using a Re- 142 Auth-Request (RAR) command identifying the session via User-Name and 143 Session-Id AVPs and containing a Re-Auth-Request-Type AVP with value 144 "AUTHORIZE_ONLY". This results in initiation of a standard 145 Request/Response sequence where authorization changes are supplied. 146 As a result, in no command can Diameter AVPs have multiple potential 147 meanings. 149 1.2. Requirements Language 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 153 document are to be interpreted as described in [RFC2119]. 155 1.3. Terminology 157 This document frequently uses the following terms: 159 Network Access Server (NAS) 160 The device providing access to the network. 162 service 163 The NAS provides a service to the user, such as IEEE 802 or PPP. 165 session 166 Each service provided by the NAS to a user constitutes a session, 167 with the beginning of the session defined as the point where 168 service is first provided and the end of the session defined as the 169 point where service is ended. A user may have multiple sessions in 170 parallel or series if the NAS supports that. 172 silently discard 173 This means the implementation discards the packet without further 174 processing. The implementation SHOULD provide the capability of 175 logging the error, including the contents of the silently discarded 176 packet, and SHOULD record the event in a statistics counter. 178 2. Overview 180 This section describes the most commonly implemented features of 181 Disconnect and Change-of-Authorization packets. 183 2.1. Disconnect Messages (DM) 185 A Disconnect-Request packet is sent by the RADIUS server in order to 186 terminate a user session on a NAS and discard all associated session 187 context. The Disconnect-Request packet is sent to UDP port 3799, and 188 identifies the NAS as well as the user session to be terminated by 189 inclusion of the identification attributes described in Section 3. 191 +----------+ Disconnect-Request +----------+ 192 | | <-------------------- | | 193 | NAS | | RADIUS | 194 | | Disconnect-Response | Server | 195 | | ---------------------> | | 196 +----------+ +----------+ 198 The NAS responds to a Disconnect-Request packet sent by a RADIUS 199 server with a Disconnect-ACK if all associated session context is 200 discarded and the user session is no longer connected, or a 201 Disconnect-NAK, if the NAS was unable to disconnect the session and 202 discard all associated session context. A NAS MUST respond to a 203 Disconnect-Request including a Service-Type Attribute with an 204 unsupported value with a Disconnect-NAK; an Error-Cause Attribute 205 with value "Unsupported Service" MAY be included. A Disconnect-ACK 206 MAY contain the Attribute Acct-Terminate-Cause (49) [RFC2866] with 207 the value set to 6 for Admin-Reset. 209 A NAS supporting the "Authorize Only" Service-Type within a 210 Disconnect-Request responds with a Disconnect-NAK containing a 211 Service-Type Attribute with value "Authorize Only" and an Error-Cause 212 Attribute with value "Request Initiated". The NAS will then send an 213 Access-Request containing a Service-Type Attribute with a value of 214 "Authorize Only", along with a State Attribute. The RADIUS server 215 MUST reply to this Access-Request with an Access-Reject. 217 2.2. Change-of-Authorization Messages (CoA) 219 CoA-Request packets contain information for dynamically changing 220 session authorizations. Typically this is used to change data 221 filters. The data filters can be of either the ingress or egress 222 kind, and are sent in addition to the identification attributes as 223 described in section 3. The port used, and packet format (described 224 in Section 2.3), are the same as that for Disconnect-Request packets. 226 The following attributes MAY be sent in a CoA-Request: 228 Filter-ID (11) - Indicates the name of a data filter list 229 to be applied for the session that the 230 identification attributes map to. 232 NAS-Filter-Rule (TBD) - Provides a filter list to be applied 233 for the session that the identification 234 attributes map to. 236 +----------+ CoA-Request +----------+ 237 | | <-------------------- | | 238 | NAS | | RADIUS | 239 | | CoA-Response | Server | 240 | | ---------------------> | | 241 +----------+ +----------+ 243 The NAS responds to a CoA-Request sent by a RADIUS server with a CoA- 244 ACK if the NAS is able to successfully change the authorizations for 245 the user session, or a CoA-NAK if the Request is unsuccessful. A NAS 246 MUST respond to a CoA-Request including a Service-Type Attribute with 247 value "Authorize Only" with a CoA-NAK; a CoA-ACK MUST NOT be sent. A 248 NAS MUST respond to a CoA-Request including a Service-Type Attribute 249 with an unsupported value with a CoA-NAK; an Error-Cause Attribute 250 with value "Unsupported Service" MAY be included. 252 2.3. Packet Format 254 For either Disconnect-Request or CoA-Request packets DP port 3799 is 255 used as the destination port. For responses, the source and 256 destination ports are reversed. Exactly one RADIUS packet is 257 encapsulated in the UDP Data field. 259 A summary of the data format is shown below. The fields are 260 transmitted from left to right. 262 The packet format consists of the fields: Code, Identifier, Length, 263 Authenticator, and Attributes in Type:Length:Value (TLV) format. All 264 fields hold the same meaning as those described in RADIUS [RFC2865]. 265 The Authenticator field MUST be calculated in the same way as is 266 specified for an Accounting-Request in [RFC2866]. 268 0 1 2 3 269 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 | Code | Identifier | Length | 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 273 | | 274 | Authenticator | 275 | | 276 | | 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 | Attributes ... 279 +-+-+-+-+-+-+-+-+-+-+-+-+- 281 Code 283 The Code field is one octet, and identifies the type of RADIUS 284 packet. Packets received with an invalid Code field MUST be 285 silently discarded. RADIUS codes (decimal) for this extension are 286 assigned as follows: 288 40 - Disconnect-Request [RFC2882] 289 41 - Disconnect-ACK [RFC2882] 290 42 - Disconnect-NAK [RFC2882] 291 43 - CoA-Request [RFC2882] 292 44 - CoA-ACK [RFC2882] 293 45 - CoA-NAK [RFC2882] 295 Identifier 297 The Identifier field is one octet, and aids in matching requests 298 and replies. The RADIUS client can detect a duplicate request if 299 it has the same server source IP address and source UDP port and 300 Identifier within a short span of time. 302 Unlike RADIUS as defined in [RFC2865], the responsibility for 303 retransmission of Disconnect-Request and CoA-Request packets lies 304 with the RADIUS server. If after sending these packets, the 305 RADIUS server does not receive a response, it will retransmit. 307 The Identifier field MUST be changed whenever the content of the 308 Attributes field changes, or whenever a valid reply has been 309 received for a previous request. For retransmissions where the 310 contents are identical, the Identifier MUST remain unchanged. 312 If the RADIUS server is retransmitting a Disconnect-Request or 313 CoA-Request to the same client as before, and the Attributes 314 haven't changed, the same Request Authenticator, Identifier and 315 source port MUST be used. If any Attributes have changed, a new 316 Authenticator and Identifier MUST be used. 318 Note that if the Event-Timestamp Attribute is included, it will be 319 updated when the packet is retransmitted, changing the content of 320 the Attributes field and requiring a new Identifier and Request 321 Authenticator. 323 If the Request to a primary proxy fails, a secondary proxy must be 324 queried, if available. Issues relating to failover algorithms are 325 described in [RFC3539]. Since this represents a new request, a 326 new Request Authenticator and Identifier MUST be used. However, 327 where the RADIUS server is sending directly to the client, 328 failover typically does not make sense, since Disconnect or CoA 329 packets need to be delivered to the NAS where the session resides. 331 Length 333 The Length field is two octets. It indicates the length of the 334 packet including the Code, Identifier, Length, Authenticator and 335 Attribute fields. Octets outside the range of the Length field 336 MUST be treated as padding and ignored on reception. If the 337 packet is shorter than the Length field indicates, it MUST be 338 silently discarded. The minimum length is 20 and maximum length 339 is 4096. 341 Authenticator 343 The Authenticator field is sixteen (16) octets. The most 344 significant octet is transmitted first. This value is used to 345 authenticate packets between the RADIUS server and client. 347 Request Authenticator 349 In Request packets, the Authenticator value is a 16 octet MD5 350 [RFC1321] checksum, called the Request Authenticator. The 351 Request Authenticator is calculated the same way as for an 352 Accounting-Request, specified in [RFC2866]. 354 Note that the Request Authenticator of a Disconnect or CoA- 355 Request cannot be done the same way as the Request 356 Authenticator of a RADIUS Access-Request, because there is no 357 User-Password Attribute in a Disconnect-Request or CoA-Request. 359 Response Authenticator 361 The Authenticator field in a Response packet (e.g. Disconnect- 362 ACK, Disconnect-NAK, CoA-ACK, or CoA-NAK) is called the 363 Response Authenticator, and contains a one-way MD5 hash 364 calculated over a stream of octets consisting of the Code, 365 Identifier, Length, the Request Authenticator field from the 366 packet being replied to, and the response Attributes if any, 367 followed by the shared secret. The resulting 16 octet MD5 hash 368 value is stored in the Authenticator field of the Response 369 packet. 371 Administrative note: As noted in [RFC2865] Section 3, the secret 372 (password shared between the client and the RADIUS server) SHOULD 373 be at least as large and unguessable as a well-chosen password. 374 RADIUS clients MUST use the source IP address of the RADIUS UDP 375 packet to decide which shared secret to use, so that requests can 376 be proxied. 378 Attributes 380 In Disconnect and CoA-Request packets, all Attributes are treated 381 as mandatory. A NAS MUST respond to a CoA-Request containing one 382 or more unsupported Attributes or Attribute values with a CoA-NAK; 383 a Disconnect-Request containing one or more unsupported Attributes 384 or Attribute values MUST be answered with a Disconnect-NAK. State 385 changes resulting from a CoA-Request MUST be atomic: if the 386 Request is successful, a CoA-ACK is sent, and all requested 387 authorization changes MUST be made. If the CoA-Request is 388 unsuccessful, a CoA-NAK MUST be sent, and the requested 389 authorization changes MUST NOT be made. Similarly, a state change 390 MUST NOT occur as a result of an unsuccessful Disconnect-Request; 391 here a Disconnect-NAK MUST be sent. 393 Since within this specification attributes may be used for 394 identification, authorization or other purposes, even if a NAS 395 implements an attribute for use with RADIUS authentication and 396 accounting, it may not support inclusion of that attribute within 397 Disconnect-Request or CoA-Request packets, given the difference in 398 attribute semantics. This is true even for attributes specified 399 within [RFC2865], [RFC2868], [RFC2869], [RFC3162] or [RFC3579] as 400 allowable within Access-Accept packets. As a result, attributes 401 beyond those specified in Section 3.5 SHOULD NOT be included 402 within Disconnect or CoA packets, since this could produce 403 unpredictable results. 405 If there are any Proxy-State Attributes in a Disconnect-Request or 406 CoA-Request received from the server, the forwarding proxy or NAS 407 MUST include those Proxy-State Attributes in its response to the 408 server. 410 A forwarding proxy or NAS MUST NOT modify existing Proxy-State, 411 State, or Class Attributes present in the packet. The forwarding 412 proxy or NAS MUST treat any Proxy-State attributes already in the 413 packet as opaque data. Its operation MUST NOT depend on the 414 content of Proxy-State attributes added by previous proxies. The 415 forwarding proxy MUST NOT modify any other Proxy-State Attributes 416 that were in the packet; it may choose not to forward them, but it 417 MUST NOT change their contents. If the forwarding proxy omits the 418 Proxy-State Attributes in the request, it MUST attach them to the 419 response before sending it. 421 When the proxy forwards a Disconnect or CoA-Request, it MAY add a 422 Proxy-State Attribute, but it MUST NOT add more than one. If a 423 Proxy-State Attribute is added to a packet when forwarding the 424 packet, the Proxy-State Attribute MUST be added after any existing 425 Proxy-State attributes. The forwarding proxy MUST NOT change the 426 order of any attributes of the same type, including Proxy-State. 427 Other Attributes can be placed before, after or even between the 428 Proxy-State Attributes. 430 When the proxy receives a response to a CoA-Request or Disconnect- 431 Request, it MUST remove its own Proxy-State (the last Proxy- State 432 in the packet) before forwarding the response. Since Disconnect 433 and CoA responses are authenticated on the entire packet contents, 434 the stripping of the Proxy-State Attribute invalidates the 435 integrity check - so the proxy needs to recompute it. 437 3. Attributes 439 In Disconnect-Request and CoA-Request packets, certain attributes are 440 used to uniquely identify the NAS as well as a user session on the 441 NAS. All NAS identification attributes included in a Request packet 442 MUST match in order for a Disconnect-Request or CoA-Request to be 443 successful; otherwise a Disconnect-NAK or CoA-NAK SHOULD be sent. 444 For session identification attributes, the User-Name and Acct- 445 Session-Id Attributes, if included, MUST match in order for a 446 Disconnect-Request or CoA-Request to be successful; other session 447 identification attributes SHOULD match. Where a mismatch of session 448 identification attributes is detected, a Disconnect-NAK or CoA-NAK 449 SHOULD be sent. The ability to use NAS or session identification 450 attributes to map to unique/multiple sessions is beyond the scope of 451 this document. Identification attributes include NAS and session 452 identification attributes, as described below. 454 NAS identification attributes 456 Attribute # Reference Description 457 --------- --- --------- ----------- 458 NAS-IP-Address 4 [RFC2865] The IPv4 address of the NAS. 459 NAS-Identifier 32 [RFC2865] String identifying the NAS. 460 NAS-IPv6-Address 95 [RFC3162] The IPv6 address of the NAS. 462 Session identification attributes 464 Attribute # Reference Description 465 --------- --- --------- ----------- 466 User-Name 1 [RFC2865] The name of the user 467 associated with the session. 468 NAS-Port 5 [RFC2865] The port on which the 469 session is terminated. 470 Framed-IP-Address 8 [RFC2865] The IPv4 address associated 471 with the session. 472 Called-Station-Id 30 [RFC2865] The link address to which 473 the session is connected. 474 Calling-Station-Id 31 [RFC2865] The link address from which 475 the session is connected. 476 Acct-Session-Id 44 [RFC2866] The identifier uniquely 477 identifying the session 478 on the NAS. 479 Acct-Multi-Session-Id 50 [RFC2866] The identifier uniquely 480 identifying related sessions. 481 NAS-Port-Type 61 [RFC2865] The type of port used. 482 NAS-Port-Id 87 [RFC2869] String identifying the port 483 where the session is. 484 Originating-Line-Info 94 [RFC4005] Provides information on the 485 characteristics of the line 486 from which a session 487 originated. 488 Framed-Interface-Id 96 [RFC3162] The IPv6 Interface Identifier 489 associated with the session; 490 always sent with 491 Framed-IPv6-Prefix. 492 Framed-IPv6-Prefix 97 [RFC3162] The IPv6 prefix associated 493 with the session, always sent 494 with Framed-Interface-Id. 496 To address security concerns described in Section 6.1, and to enable 497 Diameter/RADIUS translation, the User-Name Attribute SHOULD be 498 present in Disconnect-Request or CoA-Request packets; one or more 499 additional session identification attributes MAY also be present. 500 For example, where a Diameter client utilizes the same Session-Id for 501 both authorization and accounting, inclusion of an Acct-Session-Id 502 Attribute in a Disconnect-Request or CoA-Request can assist with 503 Diameter/RADIUS translation, since Diameter RAR and ASR commands 504 include a Session-Id AVP. 506 To address security concerns described in Section 6.2, one or more of 507 the NAS-IP-Address or NAS-IPv6-Address Attributes SHOULD be present 508 in Disconnect-Request or CoA-Request packets; the NAS-Identifier 509 Attribute MAY be present in addition. 511 If one or more authorization changes specified in a CoA-Request 512 cannot be carried out, or if one or more attributes or attribute- 513 values is unsupported, a CoA-NAK MUST be sent. Similarly, if there 514 are one or more unsupported attributes or attribute values in a 515 Disconnect-Request, a Disconnect-NAK MUST be sent. 517 A CoA-Request containing a Service-Type Attribute with value 518 "Authorize Only" MUST contain only NAS or session identification 519 attributes, as well as Service-Type, Nonce and State attributes. If 520 other attributes are included in such a CoA-Request, implementations 521 MUST send a CoA-NAK; an Error-Cause Attribute with value "Unsupported 522 Attribute" MAY be included. 524 A Disconnect-Request MUST contain only NAS and session identification 525 attributes (see Section 3), as well as Service-Type, Nonce and State 526 attributes. If other attributes are included in a Disconnect- 527 Request, implementations MUST send a Disconnect-NAK; an Error-Cause 528 Attribute with value "Unsupported Attribute" MAY be included. 530 3.1. State 532 [RFC2865] Section 5.44 states: 534 An Access-Request MUST contain either a User-Password or a CHAP- 535 Password or State. An Access-Request MUST NOT contain both a 536 User-Password and a CHAP-Password. If future extensions allow 537 other kinds of authentication information to be conveyed, the 538 attribute for that can be used in an Access-Request instead of 539 User-Password or CHAP-Password. 541 In order to satisfy the requirements of [RFC2865] Section 5.44, an 542 Access-Request with Service-Type="Authorize-Only" MUST contain a 543 State attribute. 545 In order to provide a State attribute to the NAS, a server sending a 546 CoA-Request or Disconnect-Request with a Service-Type value of 547 "Authorize-Only" MUST include a State Attribute, and the NAS MUST 548 include the State Attribute unchanged in the Access-Request. A NAS 549 receiving a CoA-Request or Disconnect-Request containing a Service- 550 Type value of "Authorize-Only" but lacking a State attribute MUST 551 send a CoA-NAK or Disconnect-NAK and SHOULD include an Error-Cause 552 attribute with value 402 (Missing Attribute). 554 3.2. Message-Authenticator 556 The Message-Authenticator Attribute MAY be used to authenticate and 557 integrity-protect CoA-Request, CoA-ACK, CoA-NAK, Disconnect-Request, 558 Disconnect-ACK and Disconnect-NAK packets order to prevent spoofing. 560 A RADIUS client receiving a CoA-Request or Disconnect-Request with a 561 Message-Authenticator Attribute present MUST calculate the correct 562 value of the Message-Authenticator and silently discard the packet if 563 it does not match the value sent. A RADIUS server receiving a 564 CoA/Disconnect-ACK or CoA/Disconnect-NAK with a Message-Authenticator 565 Attribute present MUST calculate the correct value of the Message- 566 Authenticator and silently discard the packet if it does not match 567 the value sent. 569 When a Message-Authenticator Attribute is included within a CoA- 570 Request or Disconnect-Request, it is calculated as follows: 572 Message-Authenticator = HMAC-MD5 (Type, Identifier, Length, 573 Request Authenticator, Attributes) 575 When the HMAC-MD5 message integrity check is calculated the 576 Request Authenticator field and Message-Authenticator Attribute 577 should be considered to be sixteen octets of zero. The Message- 578 Authenticator Attribute is calculated and inserted in the packet 579 before the Request Authenticator is calculated. 581 When a Message-Authenticator Attribute is included within a CoA- 582 ACK, CoA-NAK, Disconnect-ACK or Disconnect-NAK, it is calculated 583 as follows: 585 Message-Authenticator = HMAC-MD5 (Type, Identifier, Length, 586 Request Authenticator, Attributes) 588 When the HMAC-MD5 message integrity check is calculated the 589 Message-Authenticator Attribute should be considered to be sixteen 590 octets of zero. The Request Authenticator is taken from the 591 corresponding CoA/Disconnect-Request. The Message-Authenticator 592 is calculated and inserted in the packet before the Response 593 Authenticator is calculated. 595 3.3. Nonce 597 Description 599 Since the Request Authenticator field within CoA-Request and 600 Disconnect-Request packets does not contain a nonce within the 601 Request Authenticator field, these packets are vulnerable to 602 replay attack without the countermeasures described in Section 603 6.4. As noted in Section 6.4, replay attacks can be addressed by 604 using IPsec to protect RADIUS or by adding an Event-Timestamp 605 attribute to CoA-Request and Disconnect-Request packets. Since 606 use of the Event-Timestamp Attribute requires loose time 607 synchronization, where this is not possible an alternative replay 608 protection mechanism is required. For this purpose, a Nonce 609 Attribute MAY be included within CoA-Request, CoA-ACK, CoA-NAK, 610 Disconnect-Request, Disconnect-ACK, Disconnect-NAK and Accounting- 611 Request packets. 613 A summary of the Nonce Attribute format is shown below. The 614 fields are transmitted from left to right. 616 0 1 2 3 617 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 619 | Type | Length | Value 620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 Value (cont) | 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 624 Type 626 TBD for Nonce 628 Length 630 6 632 Value 634 The Value field is four octets, containing a randomly chosen value 635 [RFC4086]. 637 3.4. Error-Cause 639 Description 641 It is possible that the NAS cannot honor Disconnect-Request or 642 CoA-Request packets for some reason. The Error-Cause Attribute 643 provides more detail on the cause of the problem. It MAY be 644 included within Disconnect-ACK, Disconnect-NAK and CoA-NAK 645 packets. 647 A summary of the Error-Cause Attribute format is shown below. The 648 fields are transmitted from left to right. 650 0 1 2 3 651 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 653 | Type | Length | Value 654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 655 Value (cont) | 656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 658 Type 660 101 for Error-Cause 662 Length 664 6 666 Value 668 The Value field is four octets, containing an integer specifying 669 the cause of the error. Values 0-199 and 300-399 are reserved. 670 Values 200-299 represent successful completion, so that these 671 values may only be sent within Disconnect-ACK or CoA-ACK packets 672 and MUST NOT be sent within a Disconnect-NAK or CoA-NAK. Values 673 400-499 represent fatal errors committed by the RADIUS server, so 674 that they MAY be sent within CoA-NAK or Disconnect-NAK packets, 675 and MUST NOT be sent within CoA-ACK or Disconnect-ACK packets. 676 Values 500-599 represent fatal errors occurring on a NAS or RADIUS 677 proxy, so that they MAY be sent within CoA-NAK and Disconnect-NAK 678 packets, and MUST NOT be sent within CoA-ACK or Disconnect-ACK 679 packets. Error-Cause values SHOULD be logged by the RADIUS 680 server. Error-Code values (expressed in decimal) include: 682 # Value 683 --- ----- 684 201 Residual Session Context Removed 685 202 Invalid EAP Packet (Ignored) 686 401 Unsupported Attribute 687 402 Missing Attribute 688 403 NAS Identification Mismatch 689 404 Invalid Request 690 405 Unsupported Service 691 406 Unsupported Extension 692 501 Administratively Prohibited 693 502 Request Not Routable (Proxy) 694 503 Session Context Not Found 695 504 Session Context Not Removable 696 505 Other Proxy Processing Error 697 506 Resources Unavailable 698 507 Request Initiated 700 "Residual Session Context Removed" is sent in response to a 701 Disconnect-Request if the user session is no longer active, but 702 residual session context was found and successfully removed. This 703 value is only sent within a Disconnect-ACK and MUST NOT be sent 704 within a CoA-ACK, Disconnect-NAK or CoA-NAK. 706 "Invalid EAP Packet (Ignored)" is a non-fatal error that MUST NOT 707 be sent by implementations of this specification. 709 "Unsupported Attribute" is a fatal error sent if a Request 710 contains an attribute (such as a Vendor-Specific or EAP-Message 711 Attribute) that is not supported. 713 "Missing Attribute" is a fatal error sent if critical attributes 714 (such as NAS or session identification attributes) are missing 715 from a Request. 717 "NAS Identification Mismatch" is a fatal error sent if one or more 718 NAS identification attributes (see Section 3) do not match the 719 identity of the NAS receiving the Request. 721 "Invalid Request" is a fatal error sent if some other aspect of 722 the Request is invalid, such as if one or more attributes (such as 723 EAP- Message Attribute(s)) are not formatted properly. 725 "Unsupported Service" is a fatal error sent if a Service-Type 726 Attribute included with the Request is sent with an invalid or 727 unsupported value. 729 "Unsupported Extension" is a fatal error sent due to lack of 730 support for an extension such as Disconnect and/or CoA packets. 731 This will typically be sent by a proxy receiving an ICMP port 732 unreachable message after attempting to forward a Request to the 733 NAS. 735 "Administratively Prohibited" is a fatal error sent if the NAS is 736 configured to prohibit honoring of Request packets for the 737 specified session. 739 "Request Not Routable" is a fatal error which MAY be sent by a 740 RADIUS proxy and MUST NOT be sent by a NAS. It indicates that the 741 RADIUS proxy was unable to determine how to route the Request to 742 the NAS. For example, this can occur if the required entries are 743 not present in the proxy's realm routing table. 745 "Session Context Not Found" is a fatal error sent if the session 746 context identified in the Request does not exist on the NAS. 748 "Session Context Not Removable" is a fatal error sent in response 749 to a Disconnect-Request if the NAS was able to locate the session 750 context, but could not remove it for some reason. It MUST NOT be 751 sent within a CoA-ACK, CoA-NAK or Disconnect-ACK, only within a 752 Disconnect-NAK. 754 "Other Proxy Processing Error" is a fatal error sent in response 755 to a Request that could not be processed by a proxy, for reasons 756 other than routing. 758 "Resources Unavailable" is a fatal error sent when a Request could 759 not be honored due to lack of available NAS resources (memory, 760 non- volatile storage, etc.). 762 "Request Initiated" is a fatal error sent in response to a Request 763 including a Service-Type Attribute with a value of "Authorize 764 Only". It indicates that the Disconnect-Request or CoA-Request 765 has not been honored, but that a RADIUS Access-Request including a 766 Service-Type Attribute with value "Authorize Only" is being sent 767 to the RADIUS server. 769 3.5. Table of Attributes 771 The following table provides a guide to which attributes may be found 772 in which packets, and in what quantity. 774 Change-of-Authorization Messages 776 Request ACK NAK # Attribute 777 0-1 0 0 1 User-Name [Note 1] 778 0-1 0 0 4 NAS-IP-Address [Note 1] 779 0-1 0 0 5 NAS-Port [Note 1] 780 0-1 0 0-1 6 Service-Type [Note 6] 781 0-1 0 0 7 Framed-Protocol [Note 3] 782 0-1 0 0 8 Framed-IP-Address [Note 1] 783 0-1 0 0 9 Framed-IP-Netmask [Note 3] 784 0-1 0 0 10 Framed-Routing [Note 3] 785 0+ 0 0 11 Filter-ID [Note 3] 786 Request ACK NAK # Attribute 787 Request ACK NAK # Attribute 788 0-1 0 0 12 Framed-MTU [Note 3] 789 0+ 0 0 13 Framed-Compression [Note 3] 790 0+ 0 0 14 Login-IP-Host [Note 3] 791 0-1 0 0 15 Login-Service [Note 3] 792 0-1 0 0 16 Login-TCP-Port [Note 3] 793 0+ 0 0 18 Reply-Message [Note 2] 794 0-1 0 0 19 Callback-Number [Note 3] 795 0-1 0 0 20 Callback-Id [Note 3] 796 0+ 0 0 22 Framed-Route [Note 3] 797 0-1 0 0 23 Framed-IPX-Network [Note 3] 798 0-1 0-1 0-1 24 State [Note 7] 799 0+ 0 0 25 Class [Note 3] 800 0+ 0 0 26 Vendor-Specific [Note 3] 801 0-1 0 0 27 Session-Timeout [Note 3] 802 0-1 0 0 28 Idle-Timeout [Note 3] 803 0-1 0 0 29 Termination-Action [Note 3] 804 0-1 0 0 30 Called-Station-Id [Note 1] 805 0-1 0 0 31 Calling-Station-Id [Note 1] 806 0-1 0 0 32 NAS-Identifier [Note 1] 807 0+ 0+ 0+ 33 Proxy-State 808 0-1 0 0 34 Login-LAT-Service [Note 3] 809 0-1 0 0 35 Login-LAT-Node [Note 3] 810 0-1 0 0 36 Login-LAT-Group [Note 3] 811 0-1 0 0 37 Framed-AppleTalk-Link [Note 3] 812 0+ 0 0 38 Framed-AppleTalk-Network [Note 3] 813 0-1 0 0 39 Framed-AppleTalk-Zone [Note 3] 814 0-1 0 0 44 Acct-Session-Id [Note 1] 815 0-1 0 0 50 Acct-Multi-Session-Id [Note 1] 816 0-1 0-1 0-1 55 Event-Timestamp 817 0-1 0 0 61 NAS-Port-Type [Note 1] 818 0-1 0 0 62 Port-Limit [Note 3] 819 0-1 0 0 63 Login-LAT-Port [Note 3] 820 0+ 0 0 64 Tunnel-Type [Note 5] 821 0+ 0 0 65 Tunnel-Medium-Type [Note 5] 822 0+ 0 0 66 Tunnel-Client-Endpoint [Note 5] 823 0+ 0 0 67 Tunnel-Server-Endpoint [Note 5] 824 0+ 0 0 69 Tunnel-Password [Note 5] 825 0-1 0 0 71 ARAP-Features [Note 3] 826 0-1 0 0 72 ARAP-Zone-Access [Note 3] 827 0+ 0 0 78 Configuration-Token [Note 3] 828 0+ 0-1 0 79 EAP-Message [Note 2] 829 0-1 0-1 0-1 80 Message-Authenticator 830 0+ 0 0 81 Tunnel-Private-Group-ID [Note 5] 831 0+ 0 0 82 Tunnel-Assignment-ID [Note 5] 832 0+ 0 0 83 Tunnel-Preference [Note 5] 833 0-1 0 0 85 Acct-Interim-Interval [Note 3] 834 Request ACK NAK # Attribute 835 Request ACK NAK # Attribute 836 0-1 0 0 87 NAS-Port-Id [Note 1] 837 0-1 0 0 88 Framed-Pool [Note 3] 838 0+ 0 0 90 Tunnel-Client-Auth-ID [Note 5] 839 0+ 0 0 91 Tunnel-Server-Auth-ID [Note 5] 840 0-1 0 0 94 Originating-Line-Info [Note 1] 841 0-1 0 0 95 NAS-IPv6-Address [Note 1] 842 0-1 0 0 96 Framed-Interface-Id [Note 1] 843 0+ 0 0 97 Framed-IPv6-Prefix [Note 1] 844 0+ 0 0 98 Login-IPv6-Host [Note 3] 845 0+ 0 0 99 Framed-IPv6-Route [Note 3] 846 0-1 0 0 100 Framed-IPv6-Pool [Note 3] 847 0 0 0+ 101 Error-Cause 848 0-1 0 0 TBD NAS-Filter-Rule 849 0-1 0-1 0-1 TBD Nonce [Note 8] 850 Request ACK NAK # Attribute 852 Disconnect Messages 854 Request ACK NAK # Attribute 855 0-1 0 0 1 User-Name [Note 1] 856 0-1 0 0 4 NAS-IP-Address [Note 1] 857 0-1 0 0 5 NAS-Port [Note 1] 858 0-1 0 0-1 6 Service-Type [Note 6] 859 0-1 0 0 8 Framed-IP-Address [Note 1] 860 0+ 0 0 18 Reply-Message [Note 2] 861 0-1 0-1 0-1 24 State [Note 7] 862 0+ 0 0 25 Class [Note 4] 863 0+ 0 0 26 Vendor-Specific 864 0-1 0 0 30 Called-Station-Id [Note 1] 865 0-1 0 0 31 Calling-Station-Id [Note 1] 866 0-1 0 0 32 NAS-Identifier [Note 1] 867 0+ 0+ 0+ 33 Proxy-State 868 0-1 0 0 44 Acct-Session-Id [Note 1] 869 0-1 0-1 0 49 Acct-Terminate-Cause 870 0-1 0 0 50 Acct-Multi-Session-Id [Note 1] 871 0-1 0-1 0-1 55 Event-Timestamp 872 0-1 0 0 61 NAS-Port-Type [Note 1] 873 0+ 0-1 0 79 EAP-Message [Note 2] 874 0-1 0-1 0-1 80 Message-Authenticator 875 0-1 0 0 87 NAS-Port-Id [Note 1] 876 0-1 0 0 94 Orginating-Line-Info [Note 1] 877 0-1 0 0 95 NAS-IPv6-Address [Note 1] 878 0-1 0 0 96 Framed-Interface-Id [Note 1] 879 0+ 0 0 97 Framed-IPv6-Prefix [Note 1] 880 0 0+ 0+ 101 Error-Cause 881 0-1 0-1 0-1 TBD Nonce [Note 8] 882 Request ACK NAK # Attribute 883 The following table defines the meaning of the above table entries. 885 0 This attribute MUST NOT be present in packet. 886 0+ Zero or more instances of this attribute MAY be present in packet. 887 0-1 Zero or one instance of this attribute MAY be present in packet. 888 1 Exactly one instance of this attribute MUST be present in packet. 890 [Note 1] Where NAS or session identification attributes are included 891 in Disconnect-Request or CoA-Request packets, they are used for 892 identification purposes only. These attributes MUST NOT be used for 893 purposes other than identification (e.g. within CoA-Request packets 894 to request authorization changes). 896 [Note 2] The Reply-Message Attribute is used to present a displayable 897 message to the user. The message is only displayed as a result of a 898 successful Disconnect-Request or CoA-Request (where a Disconnect-ACK 899 or CoA-ACK is subsequently sent). Where EAP is used for 900 authentication, an EAP-Message/Notification-Request Attribute is sent 901 instead, and Disconnect-ACK or CoA-ACK packets contain an EAP- 902 Message/Notification-Response Attribute. 904 [Note 3] When included within a CoA-Request, these attributes 905 represent an authorization change request. When one of these 906 attributes is omitted from a CoA-Request, the NAS assumes that the 907 attribute value is to remain unchanged. Attributes included in a 908 CoA-Request replace all existing value(s) of the same attribute(s). 910 [Note 4] When included within a successful Disconnect-Request (where 911 a Disconnect-ACK is subsequently sent), the Class Attribute SHOULD be 912 sent unmodified by the client to the accounting server in the 913 Accounting Stop packet. If the Disconnect-Request is unsuccessful, 914 then the Class Attribute is not processed. 916 [Note 5] When included within a CoA-Request, these attributes 917 represent an authorization change request. Where tunnel attribute(s) 918 are included within a successful CoA-Request, all existing tunnel 919 attributes are removed and replaced by the new attribute(s). 921 [Note 6] Support for the Service-Type of "Authorize Only" is OPTIONAL 922 on the NAS and RADIUS server. A NAS supporting the "Authorize Only" 923 Service-Type value within Disconnect-Request or CoA-Request packets 924 MUST respond with a Disconnect-NAK or CoA-NAK respectively, 925 containing a Service-Type Attribute with value "Authorize Only", and 926 an Error-Cause Attribute with value "Request Initiated". The NAS 927 then sends an Access-Request to the RADIUS server with a Service-Type 928 Attribute with value "Authorize Only". This Access-Request SHOULD 929 contain the NAS attributes from the Disconnect or CoA-Request, as 930 well as the session attributes from the Request legal for inclusion 931 in an Access-Request as specified in [RFC2865], [RFC2868], [RFC2869] 932 and [RFC3162]. As noted in [RFC2869] Section 5.19, a Message- 933 Authenticator attribute SHOULD be included in an Access-Request that 934 does not contain a User-Password, CHAP-Password, ARAP-Password or 935 EAP-Message Attribute. The RADIUS server should send back an Access- 936 Accept to (re-)authorize the session or an Access-Reject to refuse to 937 (re-)authorize it. 939 A NAS that does not support the Service-Type Attribute with the value 940 "Authorize Only" within a Disconnect-Request MUST respond with a 941 Disconnect-NAK including no Service-Type Attribute; an Error-Cause 942 Attribute with value "Unsupported Service" MAY be included. A NAS 943 that does not support the Service-Type Attribute with the value 944 "Authorize Only" within a CoA-Request MUST respond with a CoA-NAK 945 including no Service-Type Attribute; an Error-Cause Attribute with 946 value "Unsupported Service" MAY be included. 948 [Note 7] The State Attribute is available to be sent by the RADIUS 949 server to the NAS in a Disconnect-Request or CoA-Request packet and 950 MUST be sent unmodified from the NAS to the RADIUS server in a 951 subsequent ACK or NAK packet. If a Service-Type Attribute with value 952 "Authorize Only" is included in a Disconnect-Request or CoA-Request 953 then a State Attribute MUST be present, and MUST be sent unmodified 954 from the NAS to the RADIUS server in the resulting Access-Request 955 sent to the RADIUS server, if any. The State Attribute is also 956 available to be sent by the RADIUS server to the NAS in a CoA-Request 957 that also includes a Termination-Action Attribute with the value of 958 RADIUS-Request. If the client performs the Termination-Action by 959 sending a new Access-Request upon termination of the current session, 960 it MUST include the State Attribute unchanged in that Access-Request. 961 In either usage, the client MUST NOT interpret the Attribute locally. 962 A Disconnect- Request or CoA-Request packet must have only zero or 963 one State Attribute. Usage of the State Attribute is implementation 964 dependent. If the RADIUS server does not recognize the State 965 Attribute in the Access-Request, then it MUST send an Access-Reject. 967 [Note 8] A Nonce Attribute SHOULD be included in a CoA-Request or 968 Disconnect-Request packet that is not protected by IPsec or does not 969 contain an Event-Timestamp Attribute, so as to prevent replay 970 attacks. A Nonce Attribute MAY also be included in CoA-ACK, CoA-NAK, 971 Disconnect-ACK, Disconnect-NAK, or Accounting-Request packets. 973 4. Diameter Considerations 975 Due to differences in handling change-of-authorization requests in 976 RADIUS and Diameter, it may be difficult or impossible for a 977 Diameter/RADIUS gateway to successfully translate a Diameter Re-Auth- 978 Request (RAR) to a CoA-Request and vice versa. For example, since a 979 CoA-Request only initiates an authorization change but does not 980 initiate re-authentication, a RAR command containing a Re-Auth- 981 Request-Type AVP with value "AUTHORIZE_AUTHENTICATE" cannot be 982 directly translated to a CoA-Request. A Diameter/RADIUS gateway 983 receiving a CoA-Request containing authorization changes will need to 984 translate this into two Diameter exchange. First, the 985 Diameter/RADIUS gateway will issue a RAR command including a Session- 986 Id AVP and a Re-Auth-Request-Type AVP with value "AUTHORIZE ONLY". 987 Then the Diameter/RADIUS gateway will respond to the ensuing access 988 request with a response including the authorization attributes 989 gleaned from the CoA-Request. For the translation to be possible, 990 the CoA-Request MUST include a Acct-Session-Id Attribute. If the 991 Diameter client uses the same Session-Id for both authorization and 992 accounting, then the Diameter/RADIUS gateway can copy the contents of 993 the Acct-Session-Id Attribute into the Session-Id AVP; otherwise, it 994 will need to map the Acct-Session-Id value to an equivalent Session- 995 Id for use within a RAR command. 997 To simplify translation between RADIUS and Diameter, a server 998 compliant with this specification MAY include a Service-Type 999 Attribute with value "Authorize Only" within a CoA-Request. Such a 1000 CoA-Request MUST contain a State Attribute. A NAS supporting the 1001 "Authorize Only" Service-Type within a CoA-Request responds with a 1002 CoA-NAK containing a Service-Type Attribute with value "Authorize 1003 Only", and an Error-Cause Attribute with value "Request Initiated". 1004 The NAS will then send an Access-Request containing a Service-Type 1005 Attribute with a value of "Authorize Only", along with a State 1006 Attribute. A Diameter/RADIUS gateway receiving a CoA-Request 1007 containing a Service-Type with value "Authorize Only" translates this 1008 to a RAR with Re-Auth-Request-Type AVP with value "AUTHORIZE ONLY". 1009 The received RAA is then translated to a CoA-NAK with a Service-Type 1010 value of "Authorize Only". If the Result-Code AVP in the RAA has a 1011 value in the success category, then an Error-Cause Attribute with 1012 value "Request Initiated" is included in the CoA-NAK. If the 1013 Result-Code AVP in the RAA has a value indicating a Protocol Error or 1014 a Transient or Permanent Failure, then an alternate Error-Cause 1015 Attribute is returned as suggested below. 1017 Within Diameter, a server can request that a session be aborted by 1018 sending an Abort-Session-Request (ASR), identifying the session to be 1019 terminated using Session-ID and User-Name AVPs. The ASR command is 1020 translated to a Disconnect-Request containing an Acct-Session-Id and 1021 User-Name attribute. If the Diameter client utilizes the same 1022 Session-Id in both authorization and accounting, then the value of 1023 the Session-ID AVP may be placed in the Acct-Session-Id attribute; 1024 otherwise the value of the Session-ID AVP will need to be mapped to 1025 an appropriate Acct-Session-Id value. For a Disconnect-Request to 1026 be translatable to an ASR, an Acct-Session-Id attribute MUST be 1027 present. If the Diameter client utilizes the same Session-Id in both 1028 authorization and accounting, then the value of the Acct-Session-Id 1029 may be placed into the Session-ID AVP within the ASR; otherwise the 1030 value of the Acct-Session-Id will need to be mapped to an appropriate 1031 Session-ID value. 1033 An Abort-Session-Answer (ASA) command is sent in response to an ASR 1034 in order to indicate the disposition of the request. A 1035 Diameter/RADIUS gateway receiving a Disconnect-ACK translates this to 1036 an ASA command with a Result-Code AVP of "DIAMETER_SUCCESS". A 1037 Disconnect-NAK received from the server is translated to an ASA 1038 command with a Result-Code AVP which depends on the value of the 1039 Error-Cause Attribute. Suggested translations between Error-Cause 1040 Attribute values and Result-Code AVP values are included below: 1042 # Error-Cause Attribute Value Result-Code AVP 1043 --- --------------------------- ------------------------ 1044 201 Residual Session Context DIAMETER_SUCCESS 1045 Removed 1046 202 Invalid EAP Packet DIAMETER_LIMITED_SUCCESS 1047 (Ignored) 1048 401 Unsupported Attribute DIAMETER_AVP_UNSUPPORTED 1049 402 Missing Attribute DIAMETER_MISSING_AVP 1050 403 NAS Identification DIAMETER_REALM_NOT_SERVED 1051 Mismatch 1052 404 Invalid Request DIAMETER_UNABLE_TO_COMPLY 1053 405 Unsupported Service DIAMETER_COMMAND_UNSUPPORTED 1054 406 Unsupported Extension DIAMETER_APPLICATION_UNSUPPORTED 1055 501 Administratively DIAMETER_AUTHORIZATION_REJECTED 1056 Prohibited 1057 502 Request Not Routable DIAMETER_UNABLE_TO_DELIVER 1058 (Proxy) 1059 503 Session Context Not Found DIAMETER_UNKNOWN_SESSION_ID 1060 504 Session Context Not DIAMETER_AUTHORIZATION_REJECTED 1061 Removable 1062 505 Other Proxy Processing DIAMETER_UNABLE_TO_COMPLY 1063 Error 1064 506 Resources Unavailable DIAMETER_RESOURCES_EXCEEDED 1065 507 Request Initiated DIAMETER_SUCCESS 1067 Since both the ASR/ASA and Disconnect-Request/Disconnect- 1068 NAK/Disconnect-ACK exchanges involve just a request and response, 1069 inclusion of an "Authorize Only" Service-Type within a Disconnect- 1070 Request is not needed to assist in Diameter/RADIUS translation, and 1071 may make translation more difficult. As a result, inclusion of a 1072 Service-Type of "Authorize Only" within a Disconnect-Request is NOT 1073 RECOMMENDED. 1075 5. IANA Considerations 1077 This specification does not create any new registries. 1079 This document uses the RADIUS [RFC2865] namespace, see 1080 . Allocation of one 1081 update for the section "RADIUS Attribute Types" is requested. The 1082 RADIUS attribute for which a value is requested is: 1084 TBD - Nonce 1086 There are six updates for the section: RADIUS Packet Type Codes. 1087 These Packet Types are allocated in [RFC3575]: 1089 40 - Disconnect-Request 1090 41 - Disconnect-ACK 1091 42 - Disconnect-NAK 1092 43 - CoA-Request 1093 44 - CoA-ACK 1094 45 - CoA-NAK 1096 A new Service-Type value for "Authorize Only" (17) is allocated in 1097 [RFC3576]. This draft also uses the UDP [RFC768] namespace, see 1098 . UDP port 3799 has 1099 been assigned [RFC3576]. This specification also utilizes the Error- 1100 Cause Attribute (101) allocated in [RFC3576], with the following 1101 decimal values: 1103 # Value 1104 --- ----- 1105 201 Residual Session Context Removed 1106 202 Invalid EAP Packet (Ignored) 1107 401 Unsupported Attribute 1108 402 Missing Attribute 1109 403 NAS Identification Mismatch 1110 404 Invalid Request 1111 405 Unsupported Service 1112 406 Unsupported Extension 1113 501 Administratively Prohibited 1114 502 Request Not Routable (Proxy) 1115 503 Session Context Not Found 1116 504 Session Context Not Removable 1117 505 Other Proxy Processing Error 1118 506 Resources Unavailable 1119 507 Request Initiated 1121 6. Security Considerations 1123 6.1. Authorization Issues 1125 Where a NAS is shared by multiple providers, it is undesirable for 1126 one provider to be able to send Disconnect-Request or CoA-Requests 1127 affecting the sessions of another provider. 1129 A NAS or RADIUS proxy MUST silently discard Disconnect-Request or 1130 CoA-Request packets from untrusted sources. By default, a RADIUS 1131 proxy SHOULD perform a "reverse path forwarding" (RPF) check to 1132 verify that a Disconnect-Request or CoA-Request originates from an 1133 authorized RADIUS server. In addition, it SHOULD be possible to 1134 explicitly authorize additional sources of Disconnect-Request or CoA- 1135 Request packets relating to certain classes of sessions. For 1136 example, a particular source can be explicitly authorized to send 1137 CoA-Request packets relating to users within a set of realms. 1139 To perform the RPF check, the proxy uses the session identification 1140 attributes included in Disconnect-Request or CoA-Request packets, in 1141 order to determine the RADIUS server(s) to which an equivalent 1142 Access-Request could be routed. If the source address of the 1143 Disconnect-Request or CoA-Request is within this set, then the 1144 Request is forwarded; otherwise it MUST be silently discarded. 1146 Typically the proxy will extract the realm from the Network Access 1147 Identifier [RFC4282] included within the User-Name Attribute, and 1148 determine the corresponding RADIUS servers in the proxy routing 1149 tables. The RADIUS servers for that realm are then compared against 1150 the source address of the packet. Where no RADIUS proxy is present, 1151 the RPF check will need to be performed by the NAS itself. 1153 Since authorization to send a Disconnect-Request or CoA-Request is 1154 determined based on the source address and the corresponding shared 1155 secret, the NASes or proxies SHOULD configure a different shared 1156 secret for each RADIUS server. 1158 6.2. Impersonation 1160 [RFC2865] Section 3 states: 1162 A RADIUS server MUST use the source IP address of the RADIUS 1163 UDP packet to decide which shared secret to use, so that 1164 RADIUS requests can be proxied. 1166 When RADIUS requests are forwarded by a proxy, the NAS-IP-Address or 1167 NAS-IPv6-Address Attributes will typically not match the source 1168 address observed by the RADIUS server. Since the NAS-Identifier 1169 Attribute need not contain an FQDN, this attribute may not be 1170 resolvable to the source address observed by the RADIUS server, even 1171 when no proxy is present. 1173 As a result, the authenticity check performed by a RADIUS server or 1174 proxy does not verify the correctness of NAS identification 1175 attributes. This makes it possible for a rogue NAS to forge NAS-IP- 1176 Address, NAS-IPv6-Address or NAS-Identifier Attributes within a 1177 RADIUS Access-Request in order to impersonate another NAS. It is 1178 also possible for a rogue NAS to forge session identification 1179 attributes such as the Called-Station-Id, Calling-Station-Id, or 1180 Originating-Line-Info [RFC4005]. This could fool the RADIUS server 1181 into sending Disconnect-Request or CoA-Request packets containing 1182 forged session identification attributes to a NAS targeted by an 1183 attacker. 1185 To address these vulnerabilities RADIUS proxies SHOULD check whether 1186 NAS identification attributes (see Section 3) match the source 1187 address of packets originating from the NAS. Where one or more 1188 attributes do not match, Disconnect-Request or CoA-Request packets 1189 SHOULD be silently discarded. 1191 Such a check may not always be possible. Since the NAS-Identifier 1192 Attribute need not correspond to an FQDN, it may not be resolvable to 1193 an IP address to be matched against the source address. Also, where 1194 a NAT exists between the RADIUS client and proxy, checking the NAS- 1195 IP-Address or NAS-IPv6-Address Attributes may not be feasible. 1197 6.3. IPsec Usage Guidelines 1199 In addition to security vulnerabilities unique to Disconnect or CoA 1200 packets, the protocol exchanges described in this document are 1201 susceptible to the same vulnerabilities as RADIUS [RFC2865]. It is 1202 RECOMMENDED that IPsec be employed to afford better security. 1204 Implementations of this specification SHOULD support IPsec [RFC2401] 1205 along with IKE [RFC2409] for key management. IPsec ESP [RFC2406] 1206 with non-null transform SHOULD be supported, and IPsec ESP with a 1207 non-null encryption transform and authentication support SHOULD be 1208 used to provide per-packet confidentiality, authentication, integrity 1209 and replay protection. IKE SHOULD be used for key management. 1211 Within RADIUS [RFC2865], a shared secret is used for hiding of 1212 Attributes such as User-Password, as well as in computation of the 1213 Response Authenticator. In RADIUS accounting [RFC2866], the shared 1214 secret is used in computation of both the Request Authenticator and 1215 the Response Authenticator. 1217 Since in RADIUS a shared secret is used to provide confidentiality as 1218 well as integrity protection and authentication, only use of IPsec 1219 ESP with a non-null transform can provide security services 1220 sufficient to substitute for RADIUS application-layer security. 1221 Therefore, where IPsec AH or ESP null is used, it will typically 1222 still be necessary to configure a RADIUS shared secret. 1224 Where RADIUS is run over IPsec ESP with a non-null transform, the 1225 secret shared between the NAS and the RADIUS server MAY NOT be 1226 configured. In this case, a shared secret of zero length MUST be 1227 assumed. However, a RADIUS server that cannot know whether incoming 1228 traffic is IPsec-protected MUST be configured with a non-null RADIUS 1229 shared secret. 1231 When IPsec ESP is used with RADIUS, per-packet authentication, 1232 integrity and replay protection MUST be used. 3DES-CBC MUST be 1233 supported as an encryption transform and AES-CBC SHOULD be supported. 1234 AES-CBC SHOULD be offered as a preferred encryption transform if 1235 supported. HMAC-SHA1-96 MUST be supported as an authentication 1236 transform. DES-CBC SHOULD NOT be used as the encryption transform. 1238 A typical IPsec policy for an IPsec-capable RADIUS client is 1239 "Initiate IPsec, from me to any destination port UDP 1812". This 1240 IPsec policy causes an IPsec SA to be set up by the RADIUS client 1241 prior to sending RADIUS traffic. If some RADIUS servers contacted by 1242 the client do not support IPsec, then a more granular policy will be 1243 required: "Initiate IPsec, from me to IPsec-Capable-RADIUS-Server, 1244 destination port UDP 1812." 1246 For a client implementing this specification the policy would be 1247 "Accept IPsec, from any to me, destination port UDP 3799". This 1248 causes the RADIUS client to accept (but not require) use of IPsec. 1249 It may not be appropriate to require IPsec for all RADIUS servers 1250 connecting to an IPsec-enabled RADIUS client, since some RADIUS 1251 servers may not support IPsec. 1253 For an IPsec-capable RADIUS server, a typical IPsec policy is "Accept 1254 IPsec, from any to me, destination port 1812". This causes the 1255 RADIUS server to accept (but not require) use of IPsec. It may not 1256 be appropriate to require IPsec for all RADIUS clients connecting to 1257 an IPsec-enabled RADIUS server, since some RADIUS clients may not 1258 support IPsec. 1260 For servers implementing this specification, the policy would be 1261 "Initiate IPsec, from me to any, destination port UDP 3799". This 1262 causes the RADIUS server to initiate IPsec when sending RADIUS 1263 extension traffic to any RADIUS client. If some RADIUS clients 1264 contacted by the server do not support IPsec, then a more granular 1265 policy will be required, such as "Initiate IPsec, from me to IPsec- 1266 capable-RADIUS-client, destination port UDP 3799". 1268 Where IPsec is used for security, and no RADIUS shared secret is 1269 configured, it is important that the RADIUS client and server perform 1270 an authorization check. Before enabling a host to act as a RADIUS 1271 client, the RADIUS server SHOULD check whether the host is authorized 1272 to provide network access. Similarly, before enabling a host to act 1273 as a RADIUS server, the RADIUS client SHOULD check whether the host 1274 is authorized for that role. 1276 RADIUS servers can be configured with the IP addresses (for IKE 1277 Aggressive Mode with pre-shared keys) or FQDNs (for certificate 1278 authentication) of RADIUS clients. Alternatively, if a separate 1279 Certification Authority (CA) exists for RADIUS clients, then the 1280 RADIUS server can configure this CA as a trust anchor [RFC3280] for 1281 use with IPsec. 1283 Similarly, RADIUS clients can be configured with the IP addresses 1284 (for IKE Aggressive Mode with pre-shared keys) or FQDNs (for 1285 certificate authentication) of RADIUS servers. Alternatively, if a 1286 separate CA exists for RADIUS servers, then the RADIUS client can 1287 configure this CA as a trust anchor for use with IPsec. 1289 Since unlike SSL/TLS, IKE does not permit certificate policies to be 1290 set on a per-port basis, certificate policies need to apply to all 1291 uses of IPsec on RADIUS clients and servers. In IPsec deployment 1292 supporting only certificate authentication, a management station 1293 initiating an IPsec-protected telnet session to the RADIUS server 1294 would need to obtain a certificate chaining to the RADIUS client CA. 1295 Issuing such a certificate migh not be appropriate if the management 1296 station was not authorized as a RADIUS client. 1298 Where RADIUS clients may obtain their IP address dynamically (such as 1299 an Access Point supporting DHCP), Main Mode with pre-shared keys 1300 [RFC2409] SHOULD NOT be used, since this requires use of a group pre- 1301 shared key; instead, Aggressive Mode SHOULD be used. Where RADIUS 1302 client addresses are statically assigned either Aggressive Mode or 1303 Main Mode MAY be used. With certificate authentication, Main Mode 1304 SHOULD be used. 1306 Care needs to be taken with IKE Phase 1 Identity Payload selection in 1307 order to enable mapping of identities to pre-shared keys even with 1308 Aggressive Mode. Where the ID_IPV4_ADDR or ID_IPV6_ADDR Identity 1309 Payloads are used and addresses are dynamically assigned, mapping of 1310 identities to keys is not possible, so that group pre-shared keys are 1311 still a practical necessity. As a result, the ID_FQDN identity 1312 payload SHOULD be employed in situations where Aggressive mode is 1313 utilized along with pre-shared keys and IP addresses are dynamically 1314 assigned. This approach also has other advantages, since it allows 1315 the RADIUS server and client to configure themselves based on the 1316 fully qualified domain name of their peers. 1318 Note that with IPsec, security services are negotiated at the 1319 granularity of an IPsec SA, so that RADIUS exchanges requiring a set 1320 of security services different from those negotiated with existing 1321 IPsec SAs will need to negotiate a new IPsec SA. Separate IPsec SAs 1322 are also advisable where quality of service considerations dictate 1323 different handling RADIUS conversations. Attempting to apply 1324 different quality of service to connections handled by the same IPsec 1325 SA can result in reordering, and falling outside the replay window. 1326 For a discussion of the issues, see [RFC2983]. 1328 6.4. Replay Protection 1330 Where IPsec replay protection is not used, a Nonce or Event-Timestamp 1331 (55) [RFC2869] Attribute SHOULD be included within CoA-Request and 1332 Disconnect-Request packets, and MAY be included within CoA-ACK, CoA- 1333 NAK, Disconnect-ACK and Disconnect-NAK packets. When the Event- 1334 Timestamp attribute is present, both the NAS and the RADIUS server 1335 MUST check that the Event-Timestamp Attribute is current within an 1336 acceptable time window. If the Event-Timestamp Attribute is not 1337 current, then the packet MUST be silently discarded. This implies 1338 the need for loose time synchronization within the network, which can 1339 be achieved by a variety of means, including SNTP, as described in 1340 [RFC4330]. 1342 Implementations SHOULD be configurable to discard CoA-Request or 1343 Disconnect-Request packets containing neither a Nonce nor an Event- 1344 Timestamp attribute. A default time window of 300 seconds is 1345 recommended. 1347 7. Example Traces 1349 Disconnect Request with User-Name: 1351 0: xxxx xxxx xxxx xxxx xxxx 2801 001c 1b23 .B.....$.-(....# 1352 16: 624c 3543 ceba 55f1 be55 a714 ca5e 0108 bL5C..U..U...^.. 1353 32: 6d63 6869 6261 1355 Disconnect Request with Acct-Session-ID: 1357 0: xxxx xxxx xxxx xxxx xxxx 2801 001e ad0d .B..... ~.(..... 1358 16: 8e53 55b6 bd02 a0cb ace6 4e38 77bd 2c0a .SU.......N8w.,. 1359 32: 3930 3233 3435 3637 90234567 1361 Disconnect Request with Framed-IP-Address: 1363 0: xxxx xxxx xxxx xxxx xxxx 2801 001a 0bda .B....."2.(..... 1364 16: 33fe 765b 05f0 fd9c c32a 2f6b 5182 0806 3.v[.....*/kQ... 1365 32: 0a00 0203 1367 8. References 1369 8.1. Normative References 1371 [RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, 1372 April 1992. 1374 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1375 Requirement Levels", RFC 2119, March 1997. 1377 [RFC2401] Atkinson, R. and S. Kent, "Security Architecture for the 1378 Internet Protocol", RFC 2401, November 1998. 1380 [RFC2406] Kent, S. and R. Atkinson, "IP Encapsulating Security Payload 1381 (ESP)", RFC 2406, November 1998 1383 [RFC2409] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)", 1384 RFC 2409, November 1998 1386 [RFC2865] Rigney, C., Rubens, A., Simpson, W. and S. Willens, "Remote 1387 Authentication Dial In User Service (RADIUS)", RFC 2865, June 1388 2000. 1390 [RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000. 1392 [RFC2869] Rigney, C., Willats W. and P. Calhoun, "RADIUS Extensions", 1393 RFC 2869, June 2000. 1395 [RFC3162] Aboba, B., Zorn, G. and D. Mitton, "RADIUS and IPv6", RFC 1396 3162, August 2001. 1398 [RFC3280] Housley, R., Polk, W., Ford, W. and D. Solo, "Internet X.509 1399 Public Key Infrastructure Certificate and Certificate 1400 Revocation List (CRL) Profile", RFC 3280, April 2002. 1402 [RFC3575] Aboba, B., "IANA Considerations for RADIUS", RFC 3575, July 1403 2003. 1405 [RFC3579] Aboba, B. and P. Calhoun, "RADIUS Support for Extensible 1406 Authentication Protocol (EAP)", RFC 3579, September 2003. 1408 [RFC4086] Eastlake, D., Schiller, J. and S. Crocker, "Randomness 1409 Requirements for Security", RFc 4086, June 2005. 1411 [RFC4282] Aboba, B., Beadles, M., Arkko, J. and P. Eronen, "The Network 1412 Access Identifier", RFC 4282, December 2005. 1414 8.2. Informative References 1416 [RFC768] Postel, J., "User Datagram Protocol", RFC 768, August 1980. 1418 [RFC2868] Zorn, G., Leifer, D., Rubens, A., Shriver, J., Holdrege, M. 1419 and I. Goyret, "RADIUS Attributes for Tunnel Protocol 1420 Support", RFC 2868, June 2000. 1422 [RFC2882] Mitton, D., "Network Access Server Requirements: Extended 1423 RADIUS Practices", RFC 2882, July 2000. 1425 [RFC2983] Black, D. "Differentiated Services and Tunnels", RFC 2983, 1426 October 2000. 1428 [RFC3539] Aboba, B. and J. Wood, "Authentication, Authorization and 1429 Accounting Transport Profile", RFC 3539, June 2003. 1431 [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J. 1432 Arkko, "Diameter Base Protocol", RFC 3588, September 2003. 1434 [RFC3576] Chiba, M., Dommety, G., Eklund, M., Mitton, D. and B. Aboba, 1435 "Dynamic Authorization Extensions to Remote Authentication 1436 Dial In User Service (RADIUS)", RFC 3576, July 2003. 1438 [RFC4005] Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter 1439 Network Access Server Application", RFC 4005, August 2005. 1441 [RFC4330] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for 1442 IPv4, IPv6 and OSI", RFC 4330, January 2006. 1444 [MD5Attack] 1445 Dobbertin, H., "The Status of MD5 After a Recent Attack", 1446 CryptoBytes Vol.2 No.2, Summer 1996. 1448 Acknowledgments 1450 This protocol was first developed and distributed by Ascend 1451 Communications. Example code was distributed in their free server 1452 kit. 1454 The authors would like to acknowledge the valuable suggestions and 1455 feedback from the following people: 1457 Avi Lior , 1458 Randy Bush , 1459 Steve Bellovin 1460 Glen Zorn , 1461 Mark Jones , 1462 Claudio Lapidus , 1463 Anurag Batta , 1464 Kuntal Chowdhury , and 1465 Tim Moore . 1466 Russ Housley 1468 Authors' Addresses 1470 Murtaza Chiba 1471 Cisco Systems, Inc. 1472 170 West Tasman Dr. 1473 San Jose CA, 95134 1475 EMail: mchiba@cisco.com 1476 Phone: +1 408 525 7198 1478 Gopal Dommety 1479 Cisco Systems, Inc. 1480 170 West Tasman Dr. 1481 San Jose, CA 95134 1483 EMail: gdommety@cisco.com 1484 Phone: +1 408 525 1404 1486 Mark Eklund 1487 Cisco Systems, Inc. 1488 170 West Tasman Dr. 1489 San Jose, CA 95134 1491 EMail: meklund@cisco.com 1492 Phone: +1 865 671 6255 1494 David Mitton 1495 RSA Security, Inc. 1496 174 Middlesex Turnpike 1497 Bedford, MA 01730 1499 EMail: dmitton@circularnetworks.com 1501 Bernard Aboba 1502 Microsoft Corporation 1503 One Microsoft Way 1504 Redmond, WA 98052 1505 EMail: bernarda@microsoft.com 1506 Phone: +1 425 706 6605 1507 Fax: +1 425 936 7329 1509 Appendix A - Changes from RFC 3576 1511 This Appendix lists the major changes between [RFC3576] and this 1512 document. Minor changes, including style, grammar, spelling, and 1513 editorial changes are not mentioned here. 1515 o Defined the Nonce Attribute for replay protection when IPsec is not 1516 used and the Event-Timestamp Attribute is not present (Sections 1, 1517 3.3, 6.4). 1519 o Added details relating to handling of the Proxy-State Attribute 1520 (Section 2.3). 1522 o Added requirements for inclusion of the State Attribute in CoA- 1523 Request or Disconnect-Request packets with a Service-Type of 1524 "Authorize Only" (Section 3.1). 1526 o Use of a Service-Type value of "Authorize Only" within a 1527 Disconnect-Request (Section 3.1) is not recommended. 1529 o Added clarification on the calculation of the Message-Authenticator 1530 Attribute (Section 3.2). 1532 o Added statement that support for "Authorize Only" Service-Type is 1533 optional (Section 3.5). 1535 o Added Diameter Considerations (Section 5). 1537 Intellectual Property Statement 1539 The IETF takes no position regarding the validity or scope of any 1540 Intellectual Property Rights or other rights that might be claimed to 1541 pertain to the implementation or use of the technology described in 1542 this document or the extent to which any license under such rights 1543 might or might not be available; nor does it represent that it has 1544 made any independent effort to identify any such rights. 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Please address the information to the IETF at ietf- 1559 ipr@ietf.org. 1561 Disclaimer of Validity 1563 This document and the information contained herein are provided on an 1564 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1565 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 1566 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 1567 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 1568 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1569 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1571 Copyright Statement 1573 Copyright (C) The IETF Trust (2007). This document is subject to the 1574 rights, licenses and restrictions contained in BCP 78, and except as 1575 set forth therein, the authors retain all their rights. 1577 Acknowledgment 1579 Funding for the RFC Editor function is currently provided by the 1580 Internet Society. 1582 Open issues 1584 Open issues relating to this specification are tracked on the 1585 following web site: 1587 http://www.drizzle.com/~aboba/RADEXT/