The Simple Network Management Protocol (SNMP) forms part of the internet protocol suite as defined by the Internet Engineering Task Force. The protocol can support monitoring of network-attached devices for any conditions that warrant administrative attention. The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... The application layer is the seventh level of the seven-layer OSI model. ... The File Transfer Protocol (FTP) is a software standard for transferring computer files between machines with widely different operating systems. ... HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ... The Internet Message Access Protocol (commonly known as IMAP, and previously called Interactive Mail Access Protocol) is an application layer Internet protocol used for accessing email on a remote server from a local client. ... Internet Relay Chat (IRC) is a form of instant communication over the Internet. ... The Network News Transfer Protocol or NNTP is an Internet application protocol used primarily for reading and posting Usenet articles, as well as transferring news among news servers. ... Post Office Protocol version 3 (POP3) is an application layer Internet standard protocol used to retrieve email from a remote server to a local client over a TCP/IP connection. ... Session Initiation Protocol (SIP) is a protocol developed by the IETF MMUSIC Working Group and proposed standard for initiating, modifying, and terminating an interactive user session that involves multimedia elements such as video, voice, instant messaging, online games, and virtual reality. ... Simple Mail Transfer Protocol (SMTP) is the de facto standard for email transmission across the Internet. ... In computing, Secure Shell or SSH is both a computer program and an associated network protocol designed for logging into and executing commands on a networked computer. ... Telnet is a network protocol used on the Internet or local area network LAN connections. ... BitTorrent is the protocol and the name of the peer-to-peer (P2P) file distribution tool written by programmer Bram Cohen and debuted at CodeCon 2002. ... WebSphere MQ [1] (known as MQSeries until 2002) is IBMs Message Oriented Middleware offering. ... The Datagram Congestion Control Protocol (DCCP) is a message-oriented transport layer protocol that is currently under development in the IETF. Applications that might make use of DCCP include those with timing constraints on the delivery of data such that reliable in-order delivery, when combined with congestion control, is... The Stream Control Transmission Protocol (SCTP) is a transport layer protocol defined in 2000 by the IETF Signaling Transport (SIGTRAN) working group. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... The Real-time Transport Protocol (or RTP) defines a standardized packet format for delivering audio and video over the Internet. ... The User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... Internet Light is a transport layer communication protocol designed at Bell Labs for the 9P protocol in Plan 9. ... The Reliable User Datagram Protocol (RUDP) is a transport layer protocol designed at Bell Labs for the Plan 9 operating system. ... The network layer is level three of the seven level OSI model. ... IPv4 is version 4 of the Internet Protocol (IP). ... This article may be confusing for some readers, and should be edited to enhance clarity. ... The data link layer is layer two of the seven-layer OSI model. ... Ethernet (this name comes from the physical concept of ether) is a frame-based computer networking technology for local area networks (LANs). ... Wi-Fi (sometimes written ttt, WiFi, Wifi, wifi) is a trademark for sets of product compatibility standards for wireless local area networks (WLANs). ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... In computing, the Point-to-Point Protocol, or PPP, is commonly used to establish a direct connection between two nodes. ... The physical layer is level one in the seven level OSI model of computer networking. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... EIA-422 (formerly RS-422) is a serial data communication protocol which specifies 4 wire, full-duplex, differential line, multi-drop communications. ... RS-449 - Wikipedia /**/ @import /skins/monobook/IE50Fixes. ... EIA-485 (formerly RS-485 or RS485) is an OSI Model Physical layer electrical specification of a two-wire, half-duplex, multipoint serial connection. ... 10BASE2 cable showing BNC Connector end. ... FUCK！ ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... The Internet Engineering Task Force (IETF) is charged with developing and promoting Internet standards. ... In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. ... The word monitor derives from the Latin word for warner or warning. ...

Architecture

Architecturally, the SNMP framework has three fundamental components: In general, a things components are its parts; the things that compose it. ...

1. Master Agents
2. Subagents
3. Management Stations

Within the SNMP architecture, a management information base (MIB) models each managed subsystem with a subsystem-specific definition. A MIB module specifies precisely the management data and operations that a subagent makes possible. This model permits management across all layers of the OSI reference model and extending into applications such as databases, email, and the J2EE reference model. A management information base (MIB) comprises a collection of objects in a (virtual) database used to manage entities (such as routers and switches) in a network. ... A layer is the following: In abstraction, a layer is an abstract place conceived as having depth. ... Application has the following meanings: In general, an application is using something abstract for a more concrete use. ... A database is an organized collection of data. ... E-mail, or email, is short for electronic mail and is a method of composing, sending, and receiving messages over electronic communication systems. ... J2EE is an object model reference for the J2EE Web server and application server environment. ...

The manager or management station provides the third component. It functions as the equivalent of a client in a client-server architecture. It issues requests for management operations on behalf of an administrator or application, and receives traps from agents as well. In computing, a client is a system that accesses a (remote) service on another computer by some kind of network. ... Client/Server is a network application architecture which separates the client (usually the graphical user interface) from the server. ... This site was cracked by lysp ... Application has the following meanings: In general, an application is using something abstract for a more concrete use. ... Exception handling is a programming language construct or computer hardware mechanism designed to handle runtime errors or other problems (exceptions) which occur during the execution of a computer program. ...

The SNMP protocol operates at the application layer (layer 7) of the OSI model. It specified (in version 1) five core protocol data units (PDUs): The application layer is the seventh level of the seven-layer OSI model. ... The Open Systems Interconnection Reference Model (OSI Model or OSI Reference Model for short) is a layered abstract description for communications and computer network protocol design, developed as part of the Open Systems Interconnect initiative. ... In telecommunications, the term protocol data unit (PDU) has the following meanings: Information that is delivered as a unit among peer entities of a network and that may contain control information, address information, or data. ...

1. GET REQUEST, used to retrieve a piece of management information.
2. GETNEXT REQUEST, used iteratively to retrieve sequences of management information.
3. GET RESPONSE
4. SET, used to make a change to a managed subsystem.
5. TRAP, used to report an alert or other asynchronous event about a managed subsystem. In SNMPv1, asynchronous event reports are called traps while they are called notifications in later versions of SNMP. In SMIv1 MIB modules, traps are defined using the TRAP-TYPE macro, in SMIv2 MIB modules, traps are defined using the NOTIFICATION-TYPE macro.

Other PDUs were added in later versions, including: There are many kinds of events. ... There are many kinds of events. ...

1. GETBULK REQUEST, a faster iterator used to retrieve sequences of management information.
2. INFORM, an acknowledged trap.

Typically, SNMP uses UDP ports 161 for the agent and 162 for the manager.

Development and Usage

Version 1

The first RFCs for SNMP, now known as Simple Network Management Protocol version 1, appeared in 1988: A Request for Comments (RFC) document is one of a series of numbered Internet informational documents and standards very widely followed by both commercial software and freeware in the Internet and Unix communities. ...

• RFC 1065 - Structure and identification of management information for TCP/IP-based internets
• RFC 1066 - Management information base for network management of TCP/IP-based internets
• RFC 1067 - A simple network management protocol

Version 1 has been criticized for its poor security. Authentication of clients is performed only by a "community string", in effect a type of password, which is transmitted in cleartext.

Version 2

Version 2 was not widely adopted due to serious disagreements over the security framework in the standard.

Simple Network Management Protocol version 2 (RFC 1441-RFC 1452), also known as SNMP v2 or SNMP v2p, revises version 1 and includes improvements in the areas of performance, security, confidentiality, and manager-to-manager communications. It introduced GETBULK, an alternative to iterative GETNEXTs for retrieving large amounts of management data in a single request. However, the new party-based security system in SNMP v2, viewed by many as overly complex, was not widely accepted. Community-Based Simple Network Management Protocol version 2, or SNMP v2c, is defined in RFC 1901-RFC 1908. In its initial stages, this was also informally known as SNMP v1.5. SNMP v2c comprises SNMP v2 without the controversial new SNMP v2 security model, using instead the simple community-based security scheme of SNMP v1. While officially only a "Draft Standard", this is widely considered the de facto SNMP v2 standard. De facto is a Latin expression that means in fact or in practice. It is commonly used as opposed to de jure (meaning by law) when referring to matters of law or governance or technique (such as standards), that are found in the common experience as created or developed without...

User-Based Simple Network Management Protocol version 2, or SNMP v2u, is defined in RFC 1909-RFC 1910. This is a compromise that attempts to offer greater security than SNMP v1, but without incurring the high complexity of SNMP v2. A variant of this was commercialized as SNMP v2*, and the mechanism was eventually adopted as one of two security frameworks in SNMP v3.

Version 3

The Internet Engineering Task Force (IETF) recognizes Simple Network Management Protocol version 3 as defined by RFC 3411-RFC 3418 (also known as STD0062) as the current standard version of SNMP as of 2004. The IETF considers earlier versions as "Obsolete" or "Historical". The Internet Engineering Task Force (IETF) is charged with developing and promoting Internet standards. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ...

In practice, SNMP implementations often support multiple versions: typically SNMPv1, SNMPv2c, and SNMPv3. See RFC 3584 "Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework".

Usage Example

The output below exemplifies an snmpwalk (snmpwalk is a Net-SNMP application) performed on a router, and shows general information about the device. A Linksys NAT router, popular for home and small office networks A router is a computer networking device that forwards data packets across an internetwork toward their destinations, through a process known as routing. ...

snmpwalk -c public punch system
SNMPv2-MIB::sysDescr.0 = STRING: Cisco Internetwork Operating System Software IOS (tm) C2600 Software (C2600-IO3-M), Version 12.2(15)T5, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Thu 12-Jun-03 15:49 by eaarm
SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.187
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (835747999) 96 days, 17:31:19.99
SNMPv2-MIB::sysContact.0 = STRING: wikiuser
SNMPv2-MIB::sysName.0 = STRING: punch
SNMPv2-MIB::sysLocation.0 = STRING: test
SNMPv2-MIB::sysServices.0 = INTEGER: 78
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (0) 0:00:00.00


See also

• AgentX
• SMUX

SNMP agent extensibility or AgentX is a computer networking protocol used as a standardized framework for extensible Simple Network Management Protocol agents and the procedure by which those agents process SNMP protocol messages. ... SNMP multiplexing or SMUX is a computer networking protocol used in implementing the Simple Network Management Protocol. ...

External links

• Introduction to the Simple Network Management Protocol
• AdventNet SNMP API
• SimpleWeb
• http://www.henrys.de/daniel/download/SNMP.HTM
• SNMP FAQ part 1
• SNMP FAQ part 2
• Implementations:
  • Net-SNMP: Open source SNMP implementation
  • Netsnmpj: Open source SNMP for Java
  • OpenSNMP: multi-threaded SNMPv3 engine
• Cisco:
  • Configuring SNMP Support
  • Cisco SNMP command reference
  • Cisco IOS MIB Tools
• RFCs:
  • RFC 1065 - Obsolete -Structure and Identification of Management Information for TCP/IP-based internets
  • RFC 1066 - Obsolete - Management Information Base for Network Management of TCP/IP-based internets
  • RFC 1067 - Obsolete - A Simple Network Management Protocol
  • RFC 1098 - Obsolete - A Simple Network Management Protocol (SNMP)
  • RFC 1155 - Structure and Identification of Management Information for TCP/IP-based Internets
  • RFC 1156 - Management Information Base for Network Management of TCP/IP-based internets
  • RFC 1157 - A Simple Network Management Protocol (SNMP)
  • RFC 1158 - Obsolete - Management Information Base for Network Management of TCP/IP-based internets: MIB-II
  • RFC 1441 - Introduction to version 2 of the Internet-standard Network Management Framework
  • RFC 1448 - Obsolete - Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)
  • RFC 1449 - Obsolete - Transport Mappings for version 2 of the Simple Network Management Protocol (SNMPv2)
  • RFC 1213 - Management Information Base for Network Management of TCP/IP-based internets: MIB-II
  • RFC 1905 - Obsolete - Protocol Operations for Version 2 of the Simple Network Management Protocol (SNMPv2)
  • RFC 1906 - Obsolete - Transport Mappings for Version 2 of the Simple Network Management Protocol (SNMPv2)
  • RFC 1907 - Obsolete - Management Information Base for Version 2 of the Simple Network Management Protocol (SNMPv2)
  • RFC 2262 - Obsolete - Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)
  • RFC 2265 - Obsolete - View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)
  • RFC 2271 - Obsolete - An Architecture for Describing SNMP Management Frameworks
  • RFC 2272 - Obsolete - Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)
  • RFC 2275 - Obsolete - View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)
  • RFC 2570 - Obsolete - Introduction to Version 3 of the Internet-standard Network Management Framework
  • RFC 2571 - Obsolete - An Architecture for Describing SNMP Management Framework
  • RFC 2572 - Obsolete - Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)
  • RFC 2573 - Obsolete - SNMP Applications
  • RFC 2574 - Obsolete - User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)
  • RFC 2575 - Obsolete - View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)
  • RFC 2576 - Obsolete - Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework
  • RFC 3410 - Informational - Introduction and Applicability Statements for Internet Standard Management Framework
  • RFC 3411 - Standard 62 - An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks
  • RFC 3412 - Standard 62 - Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)
  • RFC 3413 - Standard 62 - Simple Network Management Protocol (SNMP) Application
  • RFC 3414 - Standard 62 - User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)
  • RFC 3415 - Standard 62 - View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)
  • RFC 3416 - Standard 62 - Version 2 of the Protocol Operations for the Simple Network Management Protocol (SNMP)
  • RFC 3417 - Standard 62 - Transport Mappings for the Simple Network Management Protocol (SNMP)
  • RFC 3418 - Standard 62 - Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)
  • RFC 3512 - Informational- Configuring Networks and Devices with Simple Network Management Protocol (SNMP)
  • RFC 3584 - Best Current Practice- Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework