RFC 4022
Management Information Base for the Transmission Control Protocol (TCP)
📚 RFC 4022: Management Information Base for the Transmission Control Protocol (TCP) 💖
okay bestie, this one is the TCP MIB 🎀. It's a Standards Track doc from March 2005, written by R. Raghunarayan, Ed. from Cisco Systems 💅. It obsoletes RFC 2452 and RFC 2012, which means those older versions are officially replaced by this one 🫶. It doesn't update anything.
Status of This Memo ✨
this doc is an Internet standards track protocol for the internet community, and it's literally asking people to talk about it and suggest improvements 🗣️. if you want the official standardization state, look at the current edition of "Internet Official Protocol Standards" (STD 1). distribution is unlimited, so share away 🌸.
Copyright Notice 🔒
Copyright (C) The Internet Society (2005). 📜
Abstract 🦋
this memo defines a chunk of the Management Information Base (MIB) that network management protocols use across the internet community 🌐. specifically, it describes managed objects for TCP implementations, and it's IP version independent 🙌. it also obsoletes RFCs 2452 and 2012, so that's the glow-up 💜.
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. . . . . . . . . . . . . . . . . . . . . 241. The Internet-Standard Management Framework 🧚
if you want the big-picture overview of the Internet-Standard Management Framework docs, check out section 7 of RFC 3410 [RFC3410] 📖.
managed objects live in a virtual information store called the Management Information Base (MIB) 🗂️. MIB objects are usually accessed through the Simple Network Management Protocol (SNMP) 📡. the objects are defined using the Structure of Management Information (SMI) rules. this memo is a MIB module that's compliant with 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 in this memo has two tables and a group of scalars 🔥:
- the tcp group of scalars has two sets of objects:
- parameters of a TCP protocol engine, like the retransmission algorithm in use (for example, vanj [VANJ]) and the retransmission timeout values ⏱️
- statistics of a TCP protocol engine, like counters for active and passive opens, input and output segments, and errors 📊. discontinuities in the stats are identified via the sysUpTime object, which is defined in [RFC3418] 🕰️
- the tcpConnectionTable gives you status info for all TCP connections handled by a TCP protocol engine 🔌. it also reports the operating system level processes that handle those connections 🖥️
- the tcpListenerTable gives you info about all TCP listening endpoints known by a TCP protocol engine 👂. just like the connection table, it also reports the OS level processes that handle those listening endpoints 💜
2.1. Relationship to Other MIBs 🤝
this section talks about how this TCP-MIB module connects to other MIB modules 🔗.
2.1.1. Relationship to RFC1213-MIB 🕸️
the TCP related MIB objects were first defined as part of the RFC1213-MIB, which is defined in RFC 1213 [RFC1213] 🏛️. those TCP objects were later copied into their own MIB module and published in RFC 2012 [RFC2012] in SMIv2 format 🎀.
the earlier versions of the TCP-MIB both defined the tcpConnTable, and it's been deprecated basically for two reasons 💀:
(1) The tcpConnTable only supports IPv4.
the current IETF approach is to write IP version neutral MIBs, based on the InetAddressType and InetAddress constructs defined in [RFC4001], instead of having different definitions for each IP version 🌍. this cuts down on overhead when new objects get added, since there's only one place to put them 🙌. so the approach in [RFC2452], which used separate tables, isn't continued 🙅♀️.
(2) The tcpConnTable mixes listening endpoints with connections.
connections and listening endpoints usually behave differently and get managed differently 🫠. so splitting the original tcpConnTable into two tables lets you add specific status and statistics objects for listening endpoints and connections separately 🍰.
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 isn't followed anymore 🪦. implementing 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 an Unsigned32, and it's expected to match the hrSWRunIndex of the HOST-RESOURCES-MIB [RFC2790] (if the value is smaller than 2147483647), or the sysApplElmtRunIndex of the SYSAPPL-MIB [RFC2287] 🎯. this lets management apps figure out which TCP connections belong to which OS level process, and that's been super valuable in real operational environments 💖✨.
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
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 }
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."
::= { 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 }Okay bestie, the TCP counters are up next, and they are such a vibe. 🦋 We're tracking how many connections are currently established, plus how many segments go in, out, get resent, or come in broken 💀. Here's the full set.
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."
::= { 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
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 }Next up is the connection table, which is where each live TCP connection gets its own little row 🎀. Notice that LISTEN connections live in their own table now, which is very organised of them 🧚
-- 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,
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
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
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 }Last bit for this round: the listener table, for apps waiting around to accept connections 👀 There are three different ways an application can show up in it, and the NOTE at the bottom is a total main-character moment.
-- 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
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
"The address type of tcpListenerLocalAddress. The value
should be unknown (0) if connection initiations to all
local IP addresses are accepted."
::= { tcpListenerEntry 1 }The listener table is giving main character energy 💅
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 }
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 }Next up is the deprecated TCP Connection table 🥀 it's been retired in favour of the version neutral table, but the definitions are still here, bestie 🦋
-- 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
}
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 }
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 }now the conformance info, which is basically the MIB's checklist for who gets to say they're compliant 💅
-- 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
-- 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."
MODULE -- this module
MANDATORY-GROUPS { tcpGroup }
OBJECT tcpConnState
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required."
::= { tcpMIBCompliances 1 }last MIB chunk, the units of conformance, where all the groups live 🩵
-- 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 }
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 }
END4. Acknowledgements ✨
okay so this doc contains a modified subset of RFC 1213 💖 and it updates RFC 2012 and RFC 2452 🎀 which means we owe the authors and editors of those documents a massive thank you for their excellent work 🫶. Kristine Adamson also gave super useful comments about usability and design 🌸, and the authors want to thank everyone who helped make this happen 👑
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.
- [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 🔒
okay bestie, this part is SERIOUS, so read it carefully 🫶 this MIB module has a bunch of management objects with a MAX-ACCESS of read-write. those can be sensitive or vulnerable in some networks, and SET operations in a non-secure environment without proper protection can really mess up network operations 😭
here's the list of the tables and objects and why they're risky:
- the tcpConnectionState and tcpConnState objects are read-write, which means someone could terminate ANY connection 💀 unauthorized access could cause a denial of service, so yikes
okay, now the readable stuff. some objects (anything with a MAX-ACCESS other than not-accessible) can be sensitive too, so controlling even GET and/or NOTIFY access is important 🌸 you might even want to encrypt their values when they travel over the network through SNMP 🔐
- the tcpConnectionTable and the tcpConnTable show the active connections, their status, and the processes tied to them 🦋 an attacker could use that to target known or unknown weaknesses in certain protocols and applications. and access to the connection table can have privacy implications too, since it shows detailed info about active connections
- the tcpListenerTable and the tcpConnTable tell you about listeners on an entity. the tcpListenerLocalPort and tcpConnLocalPort objects can show which ports are open on the machine and which attacks are likely to work, all without the attacker needing a port scanner 👀
ngl SNMP versions before SNMPv3 had basically no real security 😭 and even if the network is secure (like with IPSec), there's still no control over WHO on that secure network can GET or SET (read, change, create, delete) the objects in this MIB module 🙈
it is RECOMMENDED that implementers look at the security features of the SNMPv3 framework (see [RFC3410], section 8), including full support for the SNMPv3 cryptographic mechanisms for authentication and privacy 🔥
and deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. instead, it is RECOMMENDED to deploy SNMPv3 and turn on cryptographic security 💅 it's then a customer or operator responsibility to make sure the SNMP entity giving access to this MIB module is configured so only the principals (users) with legit rights can GET or SET (change, create, delete) these objects 👑
7. Contributors 🎀
this document came out of the IPv6 MIB revision team, and earlier versions got help from these lovelies 🧚
- 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 several MIBs. RFC 2012 was the base for these updates, and RFC 2452 was the first document to define the managed objects for implementations of TCP over IPv6 🌈
- Keith McCloghrie, Cisco Systems (Editor), EMail: kzm@cisco.com
- 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
Full Copyright Statement 📜
Copyright (C) The Internet Society (2005).
this document is subject to the rights, licenses and restrictions in BCP 78. apart from what's set out there, the authors keep all their rights 💜
the document and the info in it are provided "AS IS". the contributor, the organization they represent or are sponsored by (if any), the Internet Society, and the Internet Engineering Task Force all DISCLAIM ALL WARRANTIES, express or implied. that includes, but isn't limited to, any warranty that using the info won't infringe any rights, and any implied warranties of merchantability or fitness for a particular purpose 🙅♀️
Intellectual Property 🦋
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copies of IPR disclosures sent to the IETF Secretariat, assurances of licenses to be made available, and the results of attempts to get a general license for implementers or users can be found in the IETF online IPR repository at http://www.ietf.org/ipr.
the IETF invites anyone to tell it about any copyrights, patents, patent applications, or other proprietary rights that may cover technology needed to implement this standard. send that info to the IETF at ietf-ipr@ietf.org 📬
Acknowledgement 💖
funding for the RFC Editor function is currently provided by the Internet Society 🌸
📦 where this page comes from
- ietf: rfc4022 2005-03
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms