SNMP is the abbreviation of simple network monitoring protocol. It is a protocol for managing information transmission in the network, especially in LAN, depending on
Selected version.
Its use in network management comes from the fact that it allows the collection of information about various hardware and software types in a standardized manner.
Network connection device information.
Almost no network administrator gives up SNMP. On the contrary, most of them rely on it confidently because they come from many different manufacturers.
Almost all types of devices support SNMP, which helps them achieve comprehensive monitoring through SNMP technology.
Version
At present, there are three versions of SNMP. The first version was in the late 1980s when network management lacked a suitable network independent of hardware manufacturers.
The development of network management tools is quite fast.
SNMP v1 was defined in 1988, based on SGMP ( RFC 1028 ). Subsequently, it was widely accepted and used. Nearly 30 years later today.
It is still in use, which is almost an eternity. SNMP v1 provides the basic functions of data polling and is relatively easy to use. Because it
It does not include any encryption algorithm, so it will not generate much overhead. Therefore, for security reasons, SNMP v1 is only used in LAN.
Its biggest limitation is its 32-bit counter architecture, which is not enough for today 's g-level or larger networks.
CMISE / CMIP protocol is a suitable choice if users want to manage the network in WAN.
SNMP v2 supports 64-bit counters, but still sends key data in plaintext, so it does not really enhance security. If. When a user encounters SNMP v2, manufacturers or network workers mostly talk about ' SNMP v2c ', where ' c ' represents ' community '.
SNMP device credentials
SNMP v3, defined in 2002, incorporates the benefits of SNMP v2c and adds security solutions such as user accounts, authentication, and. Optional packet encryption. This enhances security and makes SNMP v3 the recommended SNMP version for security. However, it also makes.
SNMP v3 has three different security levels :
• NoAuthNoPriv-denotes no authentication and no privacy. Authentication is not required and messages are not encrypted. For obvious reasons, this should only be used for.
In a closed, secure network. • AuthNoPriv-represents authentication without privacy. Messages must be authenticated to be processed ; however, they are not added during transmission.
Secret. In theory, malicious actors can still intercept data sent between the agent and the manager during authorized transmission, but no additional. Gets or sets the request. • AuthPriv-represents authentication and privacy.
How does SNMP work ?
A network usually has at least one computer or server running monitoring software. It is a management entity. A network is likely to have some, or. Many, even many other devices : switches, routers, workstations, server racks, printers, coffee machines, or any other need.
SNMP messages are sent and received between the so-called manager and agent. Usually, the SNMP manager in the network is installed on the management entity, and the SNMP agent is installed on the managed device.
Basically, the transmission of SNMP messages can be compared to typical communication between client and server, providing pull and push technology. Pull ( or poll ) Technology is the most common type of communication, the client, like the network management software on the management entity, sends a request to request the server or be managed.
Response of the device.
SNMP message type
There are different types of SNMP messages that can be used to establish network monitoring through SNMP :
• GetRequest - This is the most common SNMP message sent to the request data by the SNMP manager. The target device returns a response message. Please.
The value. GetNextRequest-SNMP Manager can send this message type to discover what information is available on the device. From OID 0.
At the beginning, the manager can continue to send requests for the next available data until there is no more ' next ' data. Thus, users. You can find all available data on a device, even if they may not have any prior knowledge of the system or device that responded.
SetRequest - This is a command initiated by a manager for setting or changing parameters through SNMP on a proxy device or system. Value. This message type can be used to manage or update configuration settings or other parameters. But be careful !
An incorrect SetRequest may be strict. Destroy system and network settings. • Response-Response is a message sent by the device agent when the manager requests it.
When sent as a response to the GetRequest type, the packet packet. Contains the requested data or value.
In the case of SetRequest, the packet takes the newly set value as confirmation that SetRequest has successfully completed. • Trap ( v2 ) -SNMP agent sends ( ' roll out ' ) Trap is not requested by the manager.
InformRequest - Added this message type to SNMP v2, making it possible for the manager to confirm that it received trap cancellation from the agent. Breath.
Some agents are configured to continue sending trap until an inform message is received. • Report - SNMP v3 is required to use the report message. They allow the SNMP manager to determine what type of queries the remote SNMP agent detects. Question.
Depending on the error detected, the SNMP engine may attempt to send a corrected SNMP message. If this is impossible, it may be)
Pass the error indication to the application that issued the failed SNMP request. ( RFC3412 )
SNMP message transmission.
The Simple Network Management Protocol is part of the Internet Protocol Suite, which is the application layer ( Layer 7 ) protocol of the OSI model. SNMP protocol uses UDP protocol to transmit messages.
UDP packet from agent to manager is a necessary condition for successful monitoring. This is usually done in local networks. This works by default, but requires additional router configuration to allow such packets to traverse a wider network. SNMP agent receives UDP requests on port 161. Requests sent from SNMP Manager can be sent from any port.
What are OID and mib ?
OID
OID represents the object identifier. OID identifies the management object defined in the MIB file.
Examples :
On the printer, the typical objects to be monitored are different cartridge states, and there may be the number of printed files. On the switch, the code of interest.
Type objects are the incoming and outgoing traffic, as well as the packet loss rate or the number of packets sent to the broadcast address. The object ( OID ) hierarchy is often described as a tree with different levels from root to single leaf.
Examples :
Here is an example of OID structure :
Iso ( 1 ).org ( 3 ).dod ( 6 ) and ( 1 ).private ( 4 ).transition ( 868 ).product ( 2 ).chassis ( 4 )
.card ( 1 ).slotCps ( 2 ) -cpsSlotSummary ( 1 ).cpsModuleTable ( 1 ).cpsModuleEntry ( 1 )
.cpsModuleModel ( 3 ).3562.3
Or : 1.3.6.1.4.868.2.4.1.2.1.1.1.3.3562.3.
The top-level and general MIB object ids are allocated by different standard organizations such as ISO. Suppliers define their own products in the private branch of the OID tree.
MIB
MIB is the abbreviation of Management Information Base, which is an independent format of management information definition. In other words. It is said that MIBs contain oid in a well-defined way. In MIB, each object has its own definition, which defines the device in which it is managed.
Properties in.
Access through the SNMP protocol. Why do we need oid and MIBs. Every management information that can be obtained through SNMP - whether it is the memory usage of the server, the traffic on the switch, or the printer row.
Team files - all individually addressed by their OID.
This attribute is why oid is needed. They help administrators identify and monitor them. The objects in the network make monitoring meaningful. In order to make the managed entities and managed devices in the network communicate successfully, they need to know which oid is available. This is the reason why MIBs exist and why system administrators need them. Every object that must be monitored on a device must be monitored by the.
MIB provided. Therefore, administrators must ensure that all necessary MIBs are stored on SNMP agent devices and management entity systems.
Why SNMP is so common : SMI
Various factors make SNMP so common. Structure of Management Information ( SMI ) is a data class. Type and its transmission provide a general understanding and standardized structure. Also consider this link to understand why SMI is also inevitable.
The value added by SNMP protocol
Why do people use SNMP ? Well, as the name suggests, simple network management protocol, which can be used for network management. In order to manage the network, administrators need information about the network. This is the greatest value of SNMP. It collects all data from many devices and allows these data to be put into context, which again allows tracking problems, making decisions based on real data, and controlling when necessary. This is the meaning of network management. This is why system administrators will benefit from using SNMP to monitor the network.
But there is more. An appropriate monitoring tool, such as PRTG, will also help to maximize the use of data received by the administrator through SNMP and authorize each network administrator to monitor and manage their network in a timely and proactive manner.
Good organization
Tracking a large number of network devices contained in modern networks may be an adventure. Ideally, monitoring solutions construct and group devices by providing the right way to do so, and support administrators by providing a clear overview that allows for detailed introductions when needed to ensure overall system health.
Alarms and notifications
Thanks to monitoring tools, when a problem occurs, system administrators know exactly where to take action, sometimes even before the problem occurs. You know.
Timely notification is absolutely critical, so monitoring solutions should provide sufficient ways to notify administrators - such as Email, push notifications, text messages ( for example, in the absence of the Internet for security reasons ), program execution, and even smart watches. An alarm. Reporting and statistics. Network monitoring will generate a large amount of data in the monitoring database.
Let the numbers speak for themselves and use them to create reports and statistics.
Analysis not only. It can provide insight into the network and help to prove its needs to the accounting or management committee.
The visual dashboard will also help the company to achieve greater
The success. Plan ahead. Data analysis will show the trend of a single network and allow for advance planning. The results are : reliability, speed and efficiency.
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