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Network Working Group R. Raghunarayan, Ed.
Request for Comments: 4022 Cisco Systems
Obsoletes: 2452, 2012 March 2005
Category: Standards Track
Management Information Base
for the Transmission Control Protocol (TCP)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
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) in an IP version
independent manner. This memo obsoletes RFCs 2452 and 2012.
Table of Contents
1. The Internet-Standard Management Framework . . . . . . . . . 2
2. Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Relationship to Other MIBs. . . . . . . . . . . . . . . 2
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . 20
5. References. . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1. Normative References. . . . . . . . . . . . . . . . . . 20
5.2. Informative References. . . . . . . . . . . . . . . . . 21
6. Security Considerations . . . . . . . . . . . . . . . . . . . 21
7. Contributors. . . . . . . . . . . . . . . . . . . . . . . . . 23
Editor's Address. . . . . . . . . . . . . . . . . . . . . . . . . 23
Full Copyright Statement. . . . . . . . . . . . . . . . . . . . . 24
Raghunarayan Standards Track [Page 1]
RFC 4022 MIB for TCP March 2005
1. The Internet-Standard Management Framework
For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58,
RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
[RFC2580].
2. Overview
The current TCP-MIB defined in this memo consists of two tables and a
group of scalars:
- The tcp group of scalars includes two sets of objects:
o Parameters of a TCP protocol engine. These include
parameters such as the retransmission algorithm in use
(e.g., vanj [VANJ]) and the retransmission timeout values.
o Statistics of a TCP protocol engine. These include counters
for the number of active/passive opens, input/output
segments, and errors. Discontinuities in the stats are
identified identified via the sysUpTime object, defined in
[RFC3418].
- The tcpConnectionTable provides access to status information
for all TCP connections handled by a TCP protocol engine. In
addition, the table reports identification of the operating
system level processes that handle the TCP connections.
- The tcpListenerTable provides access to information about all
TCP listening endpoints known by a TCP protocol engine. And as
with the connection table, the tcpListenerTable also reports
the identification of the operating system level processes that
handle this listening TCP endpoint.
2.1. Relationship to Other MIBs
This section discusses the relationship of this TCP-MIB module to
other MIB modules.
Raghunarayan Standards Track [Page 2]
RFC 4022 MIB for TCP March 2005
2.1.1. Relationship to RFC1213-MIB
TCP related MIB objects were originally defined as part of the
RFC1213-MIB defined in RFC 1213 [RFC1213]. The TCP related objects
of the RFC1213-MIB were later copied into a separate MIB module and
published in RFC 2012 [RFC2012] in SMIv2 format.
The previous versions of the TCP-MIB both defined the tcpConnTable,
which has been deprecated basically for two reasons:
(1) The tcpConnTable only supports IPv4.
The current approach in the IETF is to write IP version neutral
MIBs, based on the InetAddressType and InetAddress constructs
defined in [RFC4001], rather than to have different definitions
for various version of IP. This reduces the amount of overhead
when new objects are introduced, as there is only one place to
add them. Hence, the approach taken in [RFC2452], of having
separate tables, is not continued.
(2) The tcpConnTable mixes listening endpoints with connections.
It turns out that connections tend to have a different behaviour
and management access pattern than listening endpoints.
Therefore, splitting the original tcpConnTable into two tables
allows for the addition of specific status and statistics objects
for listening endpoints and connections.
2.1.2. Relationship to IPV6-TCP-MIB
The IPV6-TCP-MIB defined in RFC 2452 has been moved to Historic
status because the approach of having separate IP version specific
tables is not followed anymore. Implementation of RFC 2452 is no
longer suggested.
2.1.3. Relationship to HOST-RESOURCES-MIB and SYSAPPL-MIB
The tcpConnectionTable and the tcpListenerTable report the
identification of the operating system level process that handles a
connection or a listening endpoint. The value is reported as an
Unsigned32, which is expected to be the same as the hrSWRunIndex of
the HOST-RESOURCES-MIB [RFC2790] (if the value is smaller than
2147483647) or the sysApplElmtRunIndex of the SYSAPPL-MIB [RFC2287].
This allows management applications to identify the TCP connections
that belong to an operating system level process, which has proven to
be valuable in operational environments.
Raghunarayan Standards Track [Page 3]
RFC 4022 MIB for TCP March 2005
3. Definitions
TCP-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, Integer32, Unsigned32,
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 "200502180000Z" -- 18 February 2005
ORGANIZATION
"IETF IPv6 MIB Revision Team
http://www.ietf.org/html.charters/ipv6-charter.html"
CONTACT-INFO
"Rajiv Raghunarayan (editor)
Cisco Systems Inc.
170 West Tasman Drive
San Jose, CA 95134
Phone: +1 408 853 9612
Email: <raraghun@cisco.com>
Send comments to <ipv6@ietf.org>"
DESCRIPTION
"The MIB module for managing TCP implementations.
Copyright (C) The Internet Society (2005). This version
of this MIB module is a part of RFC 4022; see the RFC
itself for full legal notices."
REVISION "200502180000Z" -- 18 February 2005
DESCRIPTION
"IP version neutral revision, published as RFC 4022."
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
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RFC 4022 MIB for TCP March 2005
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
rfc2988(5) -- RFC 2988
}
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 (0..2147483647)
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
on the algorithm used to determine the retransmission
timeout; in particular, the IETF standard algorithm
rfc2988(5) provides a minimum value."
::= { tcp 2 }
tcpRtoMax OBJECT-TYPE
SYNTAX Integer32 (0..2147483647)
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
on the algorithm used to determine the retransmission
timeout; in particular, the IETF standard algorithm
rfc2988(5) provides an upper bound (as part of an
adaptive backoff algorithm)."
::= { tcp 3 }
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RFC 4022 MIB for TCP March 2005
tcpMaxConn OBJECT-TYPE
SYNTAX Integer32 (-1 | 0..2147483647)
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 that TCP connections have made a direct
transition to the SYN-SENT state from the CLOSED state.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { 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.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { tcp 6 }
tcpAttemptFails OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times that 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 that
TCP connections have made a direct transition to the
LISTEN state from the SYN-RCVD state.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
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RFC 4022 MIB for TCP March 2005
::= { tcp 7 }
tcpEstabResets OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times that TCP connections have made a direct
transition to the CLOSED state from either the ESTABLISHED
state or the CLOSE-WAIT state.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { 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.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { 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.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
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RFC 4022 MIB for TCP March 2005
::= { 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.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { tcp 12 }
tcpInErrs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments received in error (e.g., bad
TCP checksums).
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { tcp 14 }
tcpOutRsts OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of TCP segments sent containing the RST flag.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { tcp 15 }
-- { tcp 16 } was used to represent the ipv6TcpConnTable in RFC 2452,
-- which has since been obsoleted. It MUST not be used.
tcpHCInSegs OBJECT-TYPE
SYNTAX Counter64
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of segments received, including those
received in error. This count includes segments received
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RFC 4022 MIB for TCP March 2005
on currently established connections. This object is
the 64-bit equivalent of tcpInSegs.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { 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. This object is the 64-bit
equivalent of tcpOutSegs.
Discontinuities in the value of this counter are
indicated via discontinuities in the value of sysUpTime."
::= { 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. Note that unlike earlier TCP MIBs, there
is a separate table for connections in the LISTEN state."
::= { tcp 19 }
tcpConnectionEntry OBJECT-TYPE
SYNTAX TcpConnectionEntry
MAX-ACCESS not-accessible
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,
Raghunarayan Standards Track [Page 9]
RFC 4022 MIB for TCP March 2005
tcpConnectionRemAddress,
tcpConnectionRemPort }
::= { tcpConnectionTable 1 }
TcpConnectionEntry ::= SEQUENCE {
tcpConnectionLocalAddressType InetAddressType,
tcpConnectionLocalAddress InetAddress,
tcpConnectionLocalPort InetPortNumber,
tcpConnectionRemAddressType InetAddressType,
tcpConnectionRemAddress InetAddress,
tcpConnectionRemPort InetPortNumber,
tcpConnectionState INTEGER,
tcpConnectionProcess Unsigned32
}
tcpConnectionLocalAddressType OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The address type of tcpConnectionLocalAddress."
::= { tcpConnectionEntry 1 }
tcpConnectionLocalAddress OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The local IP address for this TCP connection. The type
of this address is determined by the value of
tcpConnectionLocalAddressType.
As this object is used in the index for the
tcpConnectionTable, implementors should be
careful not to create entries that would result in OIDs
with more than 128 subidentifiers; otherwise the information
cannot be accessed by using SNMPv1, SNMPv2c, or SNMPv3."
::= { tcpConnectionEntry 2 }
tcpConnectionLocalPort OBJECT-TYPE
SYNTAX InetPortNumber
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The local port number for this TCP connection."
::= { tcpConnectionEntry 3 }
tcpConnectionRemAddressType OBJECT-TYPE
Raghunarayan Standards Track [Page 10]
RFC 4022 MIB for TCP March 2005
SYNTAX InetAddressType
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The address type of tcpConnectionRemAddress."
::= { tcpConnectionEntry 4 }
tcpConnectionRemAddress OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The remote IP address for this TCP connection. The type
of this address is determined by the value of
tcpConnectionRemAddressType.
As this object is used in the index for the
tcpConnectionTable, implementors should be
careful not to create entries that would result in OIDs
with more than 128 subidentifiers; otherwise the information
cannot be accessed by using SNMPv1, SNMPv2c, or SNMPv3."
::= { 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
Raghunarayan Standards Track [Page 11]
RFC 4022 MIB for TCP March 2005
DESCRIPTION
"The state of this TCP connection.
The value listen(2) is included only for parallelism to the
old tcpConnTable and should not be used. A connection in
LISTEN state should be present in the tcpListenerTable.
The only value that 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 the TCB (as defined in [RFC793]) of
the corresponding connection on the managed node is
deleted, 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 }
tcpConnectionProcess OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The system's process ID for the process associated with
this connection, or zero if there is no such process. This
value is expected to be the same as HOST-RESOURCES-MIB::
hrSWRunIndex or SYSAPPL-MIB::sysApplElmtRunIndex for some
row in the appropriate tables."
::= { tcpConnectionEntry 8 }
-- The TCP Listener table
tcpListenerTable OBJECT-TYPE
SYNTAX SEQUENCE OF TcpListenerEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table containing information about TCP listeners. A
listening application can be represented in three
possible ways:
1. An application that is willing to accept both IPv4 and
IPv6 datagrams is represented by
Raghunarayan Standards Track [Page 12]
RFC 4022 MIB for TCP March 2005
a tcpListenerLocalAddressType of unknown (0) and
a tcpListenerLocalAddress of ''h (a zero-length
octet-string).
2. An application that is willing to accept only IPv4 or
IPv6 datagrams is represented by a
tcpListenerLocalAddressType of the appropriate address
type and a tcpListenerLocalAddress of '0.0.0.0' or '::'
respectively.
3. An application that is listening for data destined
only to a specific IP address, but from any remote
system, is represented by a tcpListenerLocalAddressType
of an appropriate address type, with
tcpListenerLocalAddress as the specific local address.
NOTE: The address type in this table represents the
address type used for the communication, irrespective
of the higher-layer abstraction. For example, an
application using IPv6 'sockets' to communicate via
IPv4 between ::ffff:10.0.0.1 and ::ffff:10.0.0.2 would
use InetAddressType ipv4(1))."
::= { tcp 20 }
tcpListenerEntry OBJECT-TYPE
SYNTAX TcpListenerEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A conceptual row of the tcpListenerTable containing
information about a particular TCP listener."
INDEX { tcpListenerLocalAddressType,
tcpListenerLocalAddress,
tcpListenerLocalPort }
::= { tcpListenerTable 1 }
TcpListenerEntry ::= SEQUENCE {
tcpListenerLocalAddressType InetAddressType,
tcpListenerLocalAddress InetAddress,
tcpListenerLocalPort InetPortNumber,
tcpListenerProcess Unsigned32
}
tcpListenerLocalAddressType OBJECT-TYPE
SYNTAX InetAddressType
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
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RFC 4022 MIB for TCP March 2005
"The address type of tcpListenerLocalAddress. The value
should be unknown (0) if connection initiations to all
local IP addresses are accepted."
::= { tcpListenerEntry 1 }
tcpListenerLocalAddress OBJECT-TYPE
SYNTAX InetAddress
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The local IP address for this TCP connection.
The value of this object can be represented in three
possible ways, depending on the characteristics of the
listening application:
1. For an application willing to accept both IPv4 and
IPv6 datagrams, the value of this object must be
''h (a zero-length octet-string), with the value
of the corresponding tcpListenerLocalAddressType
object being unknown (0).
2. For an application willing to accept only IPv4 or
IPv6 datagrams, the value of this object must be
'0.0.0.0' or '::' respectively, with
tcpListenerLocalAddressType representing the
appropriate address type.
3. For an application which is listening for data
destined only to a specific IP address, the value
of this object is the specific local address, with
tcpListenerLocalAddressType representing the
appropriate address type.
As this object is used in the index for the
tcpListenerTable, implementors should be
careful not to create entries that would result in OIDs
with more than 128 subidentifiers; otherwise the information
cannot be accessed, using SNMPv1, SNMPv2c, or SNMPv3."
::= { tcpListenerEntry 2 }
tcpListenerLocalPort OBJECT-TYPE
SYNTAX InetPortNumber
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The local port number for this TCP connection."
::= { tcpListenerEntry 3 }
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RFC 4022 MIB for TCP March 2005
tcpListenerProcess OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The system's process ID for the process associated with
this listener, or zero if there is no such process. This
value is expected to be the same as HOST-RESOURCES-MIB::
hrSWRunIndex or SYSAPPL-MIB::sysApplElmtRunIndex for some
row in the appropriate tables."
::= { tcpListenerEntry 4 }
-- 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 }
TcpConnEntry ::= SEQUENCE {
tcpConnState INTEGER,
tcpConnLocalAddress IpAddress,
tcpConnLocalPort Integer32,
tcpConnRemAddress IpAddress,
tcpConnRemPort Integer32
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RFC 4022 MIB for TCP March 2005
}
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 that 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 the TCB (as defined in [RFC793]) of
the corresponding connection on the managed node is
deleted, 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
DESCRIPTION
"The local IP address for this TCP connection. In the case
of a connection in the listen state willing to
accept connections for any IP interface associated with the
node, the value 0.0.0.0 is used."
::= { tcpConnEntry 2 }
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tcpConnLocalPort OBJECT-TYPE
SYNTAX Integer32 (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 Integer32 (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 that implement TCP.
A number of INDEX objects cannot be
represented in the form of OBJECT clauses in SMIv2 but
have the following compliance requirements,
expressed in OBJECT clause form in this description
clause:
-- OBJECT tcpConnectionLocalAddressType
-- SYNTAX InetAddressType { ipv4(1), ipv6(2) }
-- DESCRIPTION
-- This MIB requires support for only global IPv4
Raghunarayan Standards Track [Page 17]
RFC 4022 MIB for TCP March 2005
-- and IPv6 address types.
--
-- OBJECT tcpConnectionRemAddressType
-- SYNTAX InetAddressType { ipv4(1), ipv6(2) }
-- DESCRIPTION
-- This MIB requires support for only global IPv4
-- and IPv6 address types.
--
-- OBJECT tcpListenerLocalAddressType
-- SYNTAX InetAddressType { unknown(0), ipv4(1),
-- ipv6(2) }
-- DESCRIPTION
-- This MIB requires support for only global IPv4
-- and IPv6 address types. The type unknown also
-- needs to be supported to identify a special
-- case in the listener table: a listen using
-- both IPv4 and IPv6 addresses on the device.
--
"
MODULE -- this module
MANDATORY-GROUPS { tcpBaseGroup, tcpConnectionGroup,
tcpListenerGroup }
GROUP tcpHCGroup
DESCRIPTION
"This group is mandatory for systems that are capable
of receiving or transmitting more than 1 million TCP
segments per second. 1 million segments per second will
cause a Counter32 to wrap in just over an hour."
OBJECT tcpConnectionState
SYNTAX INTEGER { closed(1), listen(2), synSent(3),
synReceived(4), established(5),
finWait1(6), finWait2(7), closeWait(8),
lastAck(9), closing(10), timeWait(11) }
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required, nor is support for the value
deleteTCB (12)."
::= { tcpMIBCompliances 2 }
tcpMIBCompliance MODULE-COMPLIANCE
STATUS deprecated
DESCRIPTION
"The compliance statement for IPv4-only systems that
implement TCP. In order to be IP version independent, this
compliance statement is deprecated in favor of
tcpMIBCompliance2. However, agents are still encouraged
to implement these objects in order to interoperate with
the deployed base of managers."
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RFC 4022 MIB for TCP March 2005
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,
tcpMaxConn, tcpActiveOpens,
tcpPassiveOpens, tcpAttemptFails,
tcpEstabResets, tcpCurrEstab, tcpInSegs,
tcpOutSegs, tcpRetransSegs,
tcpInErrs, tcpOutRsts }
STATUS current
DESCRIPTION
"The group of counters common to TCP entities."
::= { tcpMIBGroups 2 }
tcpConnectionGroup OBJECT-GROUP
OBJECTS { tcpConnectionState, tcpConnectionProcess }
STATUS current
DESCRIPTION
"The group provides general information about TCP
connections."
::= { tcpMIBGroups 3 }
tcpListenerGroup OBJECT-GROUP
OBJECTS { tcpListenerProcess }
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RFC 4022 MIB for TCP March 2005
STATUS current
DESCRIPTION
"This group has objects providing general information about
TCP listeners."
::= { tcpMIBGroups 4 }
tcpHCGroup OBJECT-GROUP
OBJECTS { tcpHCInSegs, tcpHCOutSegs }
STATUS current
DESCRIPTION
"The group of objects providing for counters of high speed
TCP implementations."
::= { tcpMIBGroups 5 }
END
4. Acknowledgements
This document contains a modified subset of RFC 1213 and updates RFC
2012 and RFC 2452. Acknowledgements are therefore due to the authors
and editors of these documents for their excellent work. Several
useful comments regarding usability and design were also received
from Kristine Adamson. The authors would like to thank all these
people for their contribution to this effort.
5. References
5.1. Normative References
[RFC793] Postel, J., "Transmission Control Protocol", STD 7, RFC
793, DARPA, September 1981.
[RFC2287] Krupczak, C. and J. Saperia, "Definitions of System-Level
Managed Objects for Applications", RFC 2287, February 1998.
[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2 (SMIv2)",
STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Textual
Conventions for SMIv2", STD 58, RFC 2579, April 1999.
[RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580, April
1999.
[RFC2790] Waldbusser, S. and P. Grillo, "Host Resources MIB", RFC
2790, March 2000.
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RFC 4022 MIB for TCP March 2005
[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.
Schoenwaelder, "Textual Conventions for Internet Network
Addresses", RFC 4001, February 2005.
5.2. Informative References
[RFC1213] McCloghrie, K. and M. Rose, "Management Information Base
for Network Management of TCP/IP-based internets", RFC
1213, March 1991.
[RFC2012] McCloghrie, K., Ed., "SNMPv2 Management Information Base
for the Transmission Control Protocol using SMIv2", RFC
2012, November 1996.
[RFC2452] Daniele, M., "IP Version 6 Management Information Base for
the Transmission Control Protocol", RFC 2452, December
1998.
[RFC2988] Paxson, V. and M. Allman, "Computing TCP's Retransmission
Timer", RFC 2988, November 2000.
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
[RFC3418] Presuhn, R., Ed., "Management Information Base (MIB) for
the Simple Network Management Protocol (SNMP)", RFC 3418,
December 2002.
[VANJ] Jacobson, V., "Congestion Avoidance and Control", SIGCOMM
1988, Stanford, California.
6. Security Considerations
There are a number of management objects defined in this MIB module
with a MAX-ACCESS clause of read-write. 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. These
are the tables and objects and their sensitivity/vulnerability:
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.
Some of the readable objects in this MIB module (i.e., objects with a
MAX-ACCESS other than not-accessible) may be considered sensitive or
vulnerable in some network environments. It is thus important to
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RFC 4022 MIB for TCP March 2005
control even GET and/or NOTIFY access to these objects and possibly
to even encrypt the values of these objects when sending them over
the network via SNMP. These are the tables and objects and their
sensitivity/vulnerability:
o The tcpConnectionTable and the tcpConnTable contain objects
providing information about the active connections on the device,
the status of these connections, and the associated processes.
This information may be used by an attacker to launch attacks
against known/unknown weakness in certain protocols/applications.
In addition, access to the connection table could also have
privacy implications, as it provides detailed information on
active connections.
o The tcpListenerTable and the tcpConnTable contain objects
providing information about listeners on an entity. For example,
the tcpListenerLocalPort and tcpConnLocalPort objects can be used
to identify what ports are open on the machine and what attacks
are likely to succeed, without the attacker having to run a port
scanner.
SNMP versions prior to SNMPv3 did not include adequate security.
Even if the network itself is secure (for example by using IPSec),
even then, there is no control as to who on the secure network is
allowed to access and GET/SET (read/change/create/delete) the objects
in this MIB module.
It is RECOMMENDED that implementers consider the security features as
provided by the SNMPv3 framework (see [RFC3410], section 8),
including full support for the SNMPv3 cryptographic mechanisms (for
authentication and privacy).
Further, deployment of SNMP versions prior to SNMPv3 is NOT
RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to
enable cryptographic security. It is then a customer/operator
responsibility to ensure that the SNMP entity giving access to an
instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them.
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RFC 4022 MIB for TCP March 2005
7. Contributors
This document is an output of the IPv6 MIB revision team, and
contributors to earlier versions of this document include:
Bill Fenner, AT&T Labs -- Research
EMail: fenner@research.att.com
Brian Haberman
EMail: brian@innovationslab.net
Shawn A. Routhier, Wind River
EMail: shawn.routhier@windriver.com
Juergen Schoenwalder, TU Braunschweig
EMail: schoenw@ibr.cs.tu-bs.de
Dave Thaler, Microsoft
EMail: dthaler@windows.microsoft.com
This document updates parts of the MIBs from several documents. RFC
2012 has been the base document for these updates, and RFC 2452 was
the first document to define the managed objects for implementations
of TCP over IPv6.
RFC 2012:
Keith McCloghrie, Cisco Systems (Editor)
EMail: kzm@cisco.com
RFC 2452:
Mike Daniele, Compaq Computer Corporation
EMail: daniele@zk3.dec.com
Editor's Address
Rajiv Raghunarayan
Cisco Systems Inc.
170 West Tasman Drive
San Jose, CA 95134
USA
EMail: raraghun@cisco.com
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RFC 4022 MIB for TCP March 2005
Full Copyright Statement
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM 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
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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