IPv6 MIB Revision Design Team Bill Fenner INTERNET-DRAFT AT&T Research Expires: August 2001 Brian Haberman Nortel Networks Keith McCloghrie Cisco Systems Juergen Schoenwalder TU Braunschweig Dave Thaler Microsoft February 2001 Management Information Base for the Transmission Control Protocol (TCP) draft-ops-rfc2012-update-00.txt Status of this Document This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This document is a product of the IPv6 MIB Revision Design Team. Comments should be addressed to the authors, or the mailing list at ipv6mib@ibr.cs.tu-bs.de. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Fenner [Page 1] INTERNET-DRAFT Expires: August 2001 February 2001 Abstract This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes managed objects used for implementations of the Transmission Control Protocol (TCP) [5] in an IP version independent manner. Table of Contents 1. The SNMP Management Framework . . . . . . . . . . . . . . . . . . 2 2. Revision History. . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5. Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . . . 15 6. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations . . . . . . . . . . . . . . . . . . . . . 17 8. Editor's Address. . . . . . . . . . . . . . . . . . . . . . . . . 18 9. Full Copyright Statement. . . . . . . . . . . . . . . . . . . . . 18 1. The SNMP Management Framework The SNMP Management Framework presently consists of five major components: o An overall architecture, described in RFC 2571 [7]. o Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in STD 16, RFC 1155 [8], STD 16, RFC 1212 [9] and RFC 1215 [10]. The second version, called SMIv2, is described in STD 58, RFC 2578 [11], STD 58, RFC 2579 [12] and STD 58, RFC 2580 [13]. o Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in STD 15, RFC 1157 [14]. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 [15] and RFC 1906 [16]. The third version of the message protocol is called SNMPv3 and described in RFC 1906 [16], RFC 2572 [17] and RFC 2574 [18]. o Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 [14]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [19]. Fenner Section 1. [Page 2] INTERNET-DRAFT Expires: August 2001 February 2001 o A set of fundamental applications described in RFC 2573 [20] and the view-based access control mechanism described in RFC 2575 [21]. A more detailed introduction to the current SNMP Management Framework can be found in RFC 2570 [22]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI. This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB. 2. Revision History Changes from first draft posted to v6mib mailing list: 23 Feb 2001 Made threshold for HC packet counters 1Mpps Added copyright statements and table of contents 21 Feb 2001 -- Juergen's changes Renamed tcpInetConn* to tcpConnection* Updated Conformance info Added missing tcpConnectionState and tcpConnState objects to SEQUENCEs 6 Feb 2001 Removed v6-only objects. Renamed inetTcp* to tcpInet* Added SIZE restriction to InetAddress index objects. (36 = 32-byte addresses plus 4-byte scope, but it's just a strawman) Fenner Section 2. [Page 3] INTERNET-DRAFT Expires: August 2001 February 2001 Used InetPortNumber TC from updated INET-ADDRESS-MIB Updated compliance statements. Added Keith to authors Added open issues section. 3. Definitions TCP-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, Integer32, Gauge32, Counter32, Counter64, IpAddress, mib-2 FROM SNMPv2-SMI MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF InetAddress, InetAddressType, InetPortNumber FROM INET-ADDRESS-MIB; tcpMIB MODULE-IDENTITY LAST-UPDATED "200102210000Z" ORGANIZATION "IETF IPv6 MIB Revision Team" CONTACT-INFO "Bill Fenner (editor) AT&T Labs -- Research 75 Willow Rd. Menlo Park, CA 94025 Phone: +1 650 330-7893 Email: " DESCRIPTION "The MIB module for managing TCP implementations." REVISION "200102210000Z" DESCRIPTION "IP version neutral revision, published as RFC XXXX." REVISION "9411010000Z" DESCRIPTION "Initial SMIv2 version, published as RFC 2012." REVISION "9103310000Z" DESCRIPTION "The initial revision of this MIB module was part of MIB-II." ::= { mib-2 49 } -- the TCP base variables group Fenner Section 3. [Page 4] INTERNET-DRAFT Expires: August 2001 February 2001 tcp OBJECT IDENTIFIER ::= { mib-2 6 } -- Scalars tcpRtoAlgorithm OBJECT-TYPE SYNTAX INTEGER { other(1), -- none of the following constant(2), -- a constant rto rsre(3), -- MIL-STD-1778, Appendix B vanj(4) -- Van Jacobson's algorithm [1] } MAX-ACCESS read-only STATUS current DESCRIPTION "The algorithm used to determine the timeout value used for retransmitting unacknowledged octets." ::= { tcp 1 } tcpRtoMin OBJECT-TYPE SYNTAX Integer32 UNITS "milliseconds" MAX-ACCESS read-only STATUS current DESCRIPTION "The minimum value permitted by a TCP implementation for the retransmission timeout, measured in milliseconds. More refined semantics for objects of this type depend upon the algorithm used to determine the retransmission timeout. In particular, when the timeout algorithm is rsre(3), an object of this type has the semantics of the LBOUND quantity described in RFC 793." ::= { tcp 2 } tcpRtoMax OBJECT-TYPE SYNTAX Integer32 UNITS "milliseconds" MAX-ACCESS read-only STATUS current DESCRIPTION "The maximum value permitted by a TCP implementation for the retransmission timeout, measured in milliseconds. More refined semantics for objects of this type depend upon the algorithm used to determine the retransmission timeout. In particular, when the timeout algorithm is rsre(3), an object of this type has the semantics of the UBOUND quantity described in RFC 793." ::= { tcp 3 } Fenner Section 3. [Page 5] INTERNET-DRAFT Expires: August 2001 February 2001 tcpMaxConn OBJECT-TYPE SYNTAX Integer32 MAX-ACCESS read-only STATUS current DESCRIPTION "The limit on the total number of TCP connections the entity can support. In entities where the maximum number of connections is dynamic, this object should contain the value -1." ::= { tcp 4 } tcpActiveOpens OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of times TCP connections have made a direct transition to the SYN-SENT state from the CLOSED state." ::= { tcp 5 } tcpPassiveOpens OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of times TCP connections have made a direct transition to the SYN-RCVD state from the LISTEN state." ::= { tcp 6 } tcpAttemptFails OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of times TCP connections have made a direct transition to the CLOSED state from either the SYN-SENT state or the SYN-RCVD state, plus the number of times TCP connections have made a direct transition to the LISTEN state from the SYN-RCVD state." ::= { tcp 7 } tcpEstabResets OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED Fenner Section 3. [Page 6] INTERNET-DRAFT Expires: August 2001 February 2001 state or the CLOSE-WAIT state." ::= { tcp 8 } tcpCurrEstab OBJECT-TYPE SYNTAX Gauge32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of TCP connections for which the current state is either ESTABLISHED or CLOSE-WAIT." ::= { tcp 9 } tcpInSegs OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of segments received, including those received in error. This count includes segments received on currently established connections." ::= { tcp 10 } tcpOutSegs OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of segments sent, including those on current connections but excluding those containing only retransmitted octets." ::= { tcp 11 } tcpRetransSegs OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of segments retransmitted - that is, the number of TCP segments transmitted containing one or more previously transmitted octets." ::= { tcp 12 } tcpInErrs OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION Fenner Section 3. [Page 7] INTERNET-DRAFT Expires: August 2001 February 2001 "The total number of segments received in error (e.g., bad TCP checksums)." ::= { tcp 14 } tcpOutRsts OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of TCP segments sent containing the RST flag." ::= { tcp 15 } tcpHCInSegs OBJECT-TYPE SYNTAX Counter64 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of segments received, including those received in error, on systems that can receive more than 1 million TCP packets per second. This count includes segments received on currently established connections." ::= { tcp 17 } tcpHCOutSegs OBJECT-TYPE SYNTAX Counter64 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of segments sent, including those on current connections but excluding those containing only retransmitted octets, on systems that can transmit more than 1 million TCP packets per second." ::= { tcp 18 } -- The TCP Connection table tcpConnectionTable OBJECT-TYPE SYNTAX SEQUENCE OF TcpConnectionEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "A table containing information about existing TCP connections or listeners." ::= { tcp 19 } tcpConnectionEntry OBJECT-TYPE SYNTAX TcpConnectionEntry MAX-ACCESS not-accessible Fenner Section 3. [Page 8] INTERNET-DRAFT Expires: August 2001 February 2001 STATUS current DESCRIPTION "A conceptual row of the tcpConnectionTable containing information about a particular current TCP connection. Each row of this table is transient, in that it ceases to exist when (or soon after) the connection makes the transition to the CLOSED state." INDEX { tcpConnectionLocalAddressType, tcpConnectionLocalAddress, tcpConnectionLocalPort, tcpConnectionRemAddressType, tcpConnectionRemAddress, tcpConnectionRemPort } ::= { tcpConnectionTable 1 } TcpConnectionEntry ::= SEQUENCE { tcpConnectionLocalAddressType InetAddressType, tcpConnectionLocalAddress InetAddress, tcpConnectionLocalPort InetPortNumber, tcpConnectionRemAddressType InetAddressType, tcpConnectionRemAddress InetAddress, tcpConnectionRemPort InetPortNumber, tcpConnectionState INTEGER } tcpConnectionLocalAddressType OBJECT-TYPE SYNTAX InetAddressType MAX-ACCESS not-accessible STATUS current DESCRIPTION "The address type of tcpConnectionLocalAddress. Only IPv4 and IPv6 addresses are expected." ::= { tcpConnectionEntry 1 } tcpConnectionLocalAddress OBJECT-TYPE SYNTAX InetAddress (SIZE(0..36)) MAX-ACCESS not-accessible STATUS current DESCRIPTION "The local IP address for this TCP connection. In the case of a connection in the listen state which is willing to accept connections for any IP interface associated with the node, a value of all zeroes is used." ::= { tcpConnectionEntry 2 } tcpConnectionLocalPort OBJECT-TYPE SYNTAX InetPortNumber MAX-ACCESS not-accessible Fenner Section 3. [Page 9] INTERNET-DRAFT Expires: August 2001 February 2001 STATUS current DESCRIPTION "The local port number for this TCP connection." ::= { tcpConnectionEntry 3 } tcpConnectionRemAddressType OBJECT-TYPE SYNTAX InetAddressType MAX-ACCESS not-accessible STATUS current DESCRIPTION "The address type of tcpConnectionRemAddress. Only IPv4 and IPv6 addresses are expected. Must be the same as tcpConnectionLocalAddressType." ::= { tcpConnectionEntry 4 } tcpConnectionRemAddress OBJECT-TYPE SYNTAX InetAddress (SIZE(0..36)) MAX-ACCESS not-accessible STATUS current DESCRIPTION "The remote IP address for this TCP connection." ::= { tcpConnectionEntry 5 } tcpConnectionRemPort OBJECT-TYPE SYNTAX InetPortNumber MAX-ACCESS not-accessible STATUS current DESCRIPTION "The remote port number for this TCP connection." ::= { tcpConnectionEntry 6 } tcpConnectionState OBJECT-TYPE SYNTAX INTEGER { closed(1), listen(2), synSent(3), synReceived(4), established(5), finWait1(6), finWait2(7), closeWait(8), lastAck(9), closing(10), timeWait(11), deleteTCB(12) } MAX-ACCESS read-write STATUS current Fenner Section 3. [Page 10] INTERNET-DRAFT Expires: August 2001 February 2001 DESCRIPTION "The state of this TCP connection. The only value which may be set by a management station is deleteTCB(12). Accordingly, it is appropriate for an agent to return a `badValue' response if a management station attempts to set this object to any other value. If a management station sets this object to the value deleteTCB(12), then this has the effect of deleting the TCB (as defined in RFC 793) of the corresponding connection on the managed node, resulting in immediate termination of the connection. As an implementation-specific option, a RST segment may be sent from the managed node to the other TCP endpoint (note however that RST segments are not sent reliably)." ::= { tcpConnectionEntry 7 } -- The deprecated TCP Connection table tcpConnTable OBJECT-TYPE SYNTAX SEQUENCE OF TcpConnEntry MAX-ACCESS not-accessible STATUS deprecated DESCRIPTION "A table containing information about existing IPv4-specific TCP connections or listeners. This table has been deprecated in favor of the version neutral tcpConnectionTable." ::= { tcp 13 } tcpConnEntry OBJECT-TYPE SYNTAX TcpConnEntry MAX-ACCESS not-accessible STATUS deprecated DESCRIPTION "A conceptual row of the tcpConnTable containing information about a particular current IPv4 TCP connection. Each row of this table is transient, in that it ceases to exist when (or soon after) the connection makes the transition to the CLOSED state." INDEX { tcpConnLocalAddress, tcpConnLocalPort, tcpConnRemAddress, tcpConnRemPort } ::= { tcpConnTable 1 } Fenner Section 3. [Page 11] INTERNET-DRAFT Expires: August 2001 February 2001 TcpConnEntry ::= SEQUENCE { tcpConnState INTEGER, tcpConnLocalAddress IpAddress, tcpConnLocalPort INTEGER, tcpConnRemAddress IpAddress, tcpConnRemPort INTEGER } tcpConnState OBJECT-TYPE SYNTAX INTEGER { closed(1), listen(2), synSent(3), synReceived(4), established(5), finWait1(6), finWait2(7), closeWait(8), lastAck(9), closing(10), timeWait(11), deleteTCB(12) } MAX-ACCESS read-write STATUS deprecated DESCRIPTION "The state of this TCP connection. The only value which may be set by a management station is deleteTCB(12). Accordingly, it is appropriate for an agent to return a `badValue' response if a management station attempts to set this object to any other value. If a management station sets this object to the value deleteTCB(12), then this has the effect of deleting the TCB (as defined in RFC 793) of the corresponding connection on the managed node, resulting in immediate termination of the connection. As an implementation-specific option, a RST segment may be sent from the managed node to the other TCP endpoint (note however that RST segments are not sent reliably)." ::= { tcpConnEntry 1 } tcpConnLocalAddress OBJECT-TYPE SYNTAX IpAddress MAX-ACCESS read-only STATUS deprecated Fenner Section 3. [Page 12] INTERNET-DRAFT Expires: August 2001 February 2001 DESCRIPTION "The local IP address for this TCP connection. In the case of a connection in the listen state which is willing to accept connections for any IP interface associated with the node, the value 0.0.0.0 is used." ::= { tcpConnEntry 2 } tcpConnLocalPort OBJECT-TYPE SYNTAX INTEGER (0..65535) MAX-ACCESS read-only STATUS deprecated DESCRIPTION "The local port number for this TCP connection." ::= { tcpConnEntry 3 } tcpConnRemAddress OBJECT-TYPE SYNTAX IpAddress MAX-ACCESS read-only STATUS deprecated DESCRIPTION "The remote IP address for this TCP connection." ::= { tcpConnEntry 4 } tcpConnRemPort OBJECT-TYPE SYNTAX INTEGER (0..65535) MAX-ACCESS read-only STATUS deprecated DESCRIPTION "The remote port number for this TCP connection." ::= { tcpConnEntry 5 } -- conformance information tcpMIBConformance OBJECT IDENTIFIER ::= { tcpMIB 2 } tcpMIBCompliances OBJECT IDENTIFIER ::= { tcpMIBConformance 1 } tcpMIBGroups OBJECT IDENTIFIER ::= { tcpMIBConformance 2 } -- compliance statements tcpMIBCompliance2 MODULE-COMPLIANCE STATUS current DESCRIPTION "The compliance statement for systems which implement TCP." Fenner Section 3. [Page 13] INTERNET-DRAFT Expires: August 2001 February 2001 MODULE -- this module MANDATORY-GROUPS { tcpBaseGroup, tcpConnectionGroup } GROUP tcpHCGroup DESCRIPTION "This group is mandatory for those systems which are capable of receiving or transmitting more than 1 million TCP packets per second. 1 million packets per second will cause a Counter32 to wrap in just over an hour." OBJECT tcpConnectionState MIN-ACCESS read-only DESCRIPTION "Write access is not required." ::= { tcpMIBCompliances 2 } tcpMIBCompliance MODULE-COMPLIANCE STATUS deprecated DESCRIPTION "The compliance statement for IPv4-only systems which implement TCP. In order to be IP version independent, this compliance statement is deprecated in favor of tcpMIBCompliance2." MODULE -- this module MANDATORY-GROUPS { tcpGroup } OBJECT tcpConnState MIN-ACCESS read-only DESCRIPTION "Write access is not required." ::= { tcpMIBCompliances 1 } -- units of conformance tcpGroup OBJECT-GROUP OBJECTS { tcpRtoAlgorithm, tcpRtoMin, tcpRtoMax, tcpMaxConn, tcpActiveOpens, tcpPassiveOpens, tcpAttemptFails, tcpEstabResets, tcpCurrEstab, tcpInSegs, tcpOutSegs, tcpRetransSegs, tcpConnState, tcpConnLocalAddress, tcpConnLocalPort, tcpConnRemAddress, tcpConnRemPort, tcpInErrs, tcpOutRsts } STATUS deprecated DESCRIPTION "The tcp group of objects providing for management of TCP entities." ::= { tcpMIBGroups 1 } tcpBaseGroup OBJECT-GROUP OBJECTS { tcpRtoAlgorithm, tcpRtoMin, tcpRtoMax, Fenner Section 3. [Page 14] INTERNET-DRAFT Expires: August 2001 February 2001 tcpMaxConn, tcpActiveOpens, tcpPassiveOpens, tcpAttemptFails, tcpEstabResets, tcpCurrEstab, tcpInSegs, tcpOutSegs, tcpRetransSegs, tcpInErrs, tcpOutRsts } STATUS current DESCRIPTION "The group of counters common to TCP entities." ::= { tcpMIBGroups 2 } tcpHCGroup OBJECT-GROUP OBJECTS { tcpHCInSegs, tcpHCOutSegs } STATUS current DESCRIPTION "The group of objects providing for counters of high speed TCP implementations." ::= { tcpMIBGroups 3 } tcpConnectionGroup OBJECT-GROUP OBJECTS { tcpConnectionState } STATUS current DESCRIPTION "The table of TCP connections." ::= { tcpMIBGroups 4 } END 4. Open Issues Per-connection byte/segment counters? Other stats? [in optional conformance group] e.g. ConnInBytes ConnOutBytes ConnInPkts ConnOutPkts ConnElapsed ConnSRTT More HC counters? v6 SIIT / IPV6_V6ONLY / ??? : does the tcpConnectionTable need something? (Erik said: But for the different types of wildcard listeners it would make sense to be able to capture the difference between: IPv4-only - bound to INADDR_ANY IPv6-only - bound to in6addr_any with the IPV6_V6ONLY socket option set both - bound to in6addr_any and the above not set [the last 2 could probably be differentiated by the remote address AF being Unknown or IPv6 -- which would require changing the DESCRIPTION] Fenner Section 4. [Page 15] INTERNET-DRAFT Expires: August 2001 February 2001 5. Acknowledgements This document contains a modified subset of RFC 1213 and updates RFC 2012 and RFC 2452. 6. References [2] Rose, M. and K. McCloghrie, "Management Information Base for Network Management of TCP/IP-based internets", RFC 1213, March 1991. [3] K. McCloghrie, "SNMPv2 Management Information Base for the Transmission Control Protocol using SMIv2", RFC 2012, November 1996. [4] Haskin, D. and S. Onishi, "IP Version 6 Management Information Base for the Transmission Control Protocol", RFC 2452, December 1998. [5] Postel, J., "Transmission Control Protocol - DARPA Internet Program Protocol Specification", STD 7, RFC 793, DARPA, September 1981. [6] Jacobson, V., "Congestion Avoidance and Control", SIGCOMM 1988, Stanford, California. [7] Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for Describing SNMP Management Frameworks", RFC 2571, April 1999. [8] Rose, M., and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based Internets", STD 16, RFC 1155, May 1990. [9] Rose, M., and K. McCloghrie, "Concise MIB Definitions", STD 16, RFC 1212, March 1991. [10] M. Rose, "A Convention for Defining Traps for use with the SNMP", RFC 1215, March 1991. [11] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., and S. Waldbusser, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. [12] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., and S. Waldbusser, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999. [13] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M., and S. Waldbusser, "Conformance Statements for SMIv2", STD 58, RFC Fenner Section 6. [Page 16] INTERNET-DRAFT Expires: August 2001 February 2001 2580, April 1999. [14] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Network Management Protocol", STD 15, RFC 1157, May 1990. [15] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Introduction to Community-based SNMPv2", RFC 1901, January 1996. [16] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Transport Mappings for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1906, January 1996. [17] Case, J., Harrington D., Presuhn R., and B. Wijnen, "Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)", RFC 2572, April 1999. [18] Blumenthal, U., and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", RFC 2574, April 1999. [19] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1905, January 1996. [20] Levi, D., Meyer, P., and B. Stewart, "SNMPv3 Applications", RFC 2573, April 1999. [21] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", RFC 2575, April 1999. [22] Case, J., Mundy, R., Partain, D., and B. Stewart, "Introduction to Version 3 of the Internet-standard Network Management Framework", RFC 2570, April 1999. 7. Security Considerations There are a number of management objects defined in this MIB that have a MAX-ACCESS clause of read-write and/or read-create. Such objects may be considered sensitive or vulnerable in some network environments. The support for SET operations in a non-secure environment without proper protection can have a negative effect on network operations. There are a number of managed objects in this MIB that may contain sensitive information. These are: Fenner Section 7. [Page 17] INTERNET-DRAFT Expires: August 2001 February 2001 o The tcpConnectionLocalPort and tcpConnLocalPort objects can be used to identify what ports are open on the machine and can thus what attacks are likely to succeed, without the attacker having to run a port scanner. o The tcpConnectionState and tcpConnState objects have a MAX-ACCESS clause of read-write, which allows termination of an arbitrary connection. Unauthorized access could cause a denial of service. It is thus important to control even GET access to these objects and possibly to even encrypt the values of these object when sending them over the network via SNMP. Not all versions of SNMP provide features for such a secure environment. SNMPv1 by itself is not a secure environment. Even if the network itself is secure (for example by using IPSec), even then, there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB. It is recommended that the implementers consider the security features as provided by the SNMPv3 framework. Specifically, the use of the User- based Security Model RFC 2574 [18] and the View-based Access Control Model RFC 2575 [21] is recommended. It is then a customer/user responsibility to ensure that the SNMP entity giving access to an instance of this MIB, is properly configured to give access to the objects only to those principals (users) that have legitimate rights to indeed GET or SET (change/create/delete) them. 8. Editor's Address Bill Fenner AT&T Labs -- Research 75 Willow Rd Menlo Park, CA 94025 USA Email: fenner@research.att.com 9. Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or Fenner Section 9. [Page 18] INTERNET-DRAFT Expires: August 2001 February 2001 assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Fenner Section 9. [Page 19]