What is SNMP?


What is SNMP(Simple Network Management Protocol)?

SNMP is a network management protocol. It works on the application layer. It was created in 1988. SNMP is defined in RFC 1065.Log messages of events are viewed by syslog. This helps the network to manage. But syslog does not provide information about devices in real time. It cannot send current status at the time of failure.

If there are thousands of devices in an organization, then checking daily which ones are working properly and which are not, will be a very tedious and huge complex process.Simple network management protocol i.e. SNMP isused to make this work easier. 


The status of any device can be achieved in real time by SNMP. Devices can also be configured by this.

What is SNMP?
What is SNMP?

Suppose a company has 300 network devices. Such as routers, switches, hubs, printers etc. Every day you have to see their status. In such a situation it is very difficult to check so many devices.

SNMP is very useful in such a situation. Current status of devices can be obtained by SNMP. This does not require moving to devices.

Versions of SNMP(Simple Network Management Protocol)

3 versions of SNMP are available.

SNMPv1 - This is the first version. Nowadays it is not used. It supports plaintext authentication. It only uses UDP.

SNMPv2 - This is more secure than the first version. It uses UDP. However it can be configured to use TCP.

SNMPv3 - It uses TCP. Provides data integrity of messages via DES. Provides MD5 authentication.

Components of Simple Network Management Protocol

SNMP consists of 3 major components.

SNMP Manager

It is also called network management station. It is a centralized system. The devices are monitored by this only. Devices only send information to it. The devices are configured by this.It is a centralized system that is used to monitor the network. It is also known as Network Management Station ie MNS.

SNMP Agent

It is a software system. It is installed on a device. It sends the information of the device to the SNMP manager.It is a software management module installed in a managed device. A managed device can be any network device such as a PC, router, sitch, server, etc.

Management Information Base

It is a collection of information. In this, information is stored hierarchically. It is accessed by SNMP.MIB contains information about the resources to be managed. These information are organized according to hierarchy. They contain object instances that are variable.

What is SNMP?
What is SNMP?

Simple Network Management Protocol Messages

7 types of messages are used in SNMP.

GetRequest -
Sent by SNMP manager to request data from SNMP agent. In its response, data is sent by the agent.

GetNextRequest - 
sent by SNMP manager to get the next information variable available on the agent device. Its response next available information is sent.This message can be sent to discover what data is available on the SNMP agent. The SNMP manager can request data continuously until there is no data left. In this way the manager can keep information about all the data available on SNMP.

GetBulkRequest - 
It was introduced in version 2. It is sent to receive a lot of information simultaneously.This message is sent to extract large amounts of data at once. It is sent by the SNMP manager to the SNMP agent. It was first introduced in SNMPv2c.

SetRequest -
Used by the SNMP manager to configure some settings on the agent.This is used by the SNMP manager to set a value on the object instance of the SNMP agent.

Response - 
The response is sent by the agent on the request of the SNMP manager.This message is sent by the agent when the manager requests it from him. When the message will be sent as gate response, then the requested data remains in that message. When it is sent as a set message, there is an acknowledgment that a new value has been set.

Trap - 
When fault occurs, agent is sent to manager without any request.These are the messages sent by the agent without requesting the manager. This message is sent when something goes wrong.

InformRequest - 
Used to find out whether a Trap message has been received by the SNMP manager.It was brought to SNMPv2C. It is used to know whether the manager has received the trap message. Agents can be configured to set traps continuously until it receives a notification message. It is similar to Trap but it also has a scnowledge that is not in Trap's X.

Configuring Simple Network Management Protocol

Configuring SNMP is very easy. For this, first you enable SNMP read / write access on the router. After this, SNMP information is configured on that router. After this the location of SNMP is configured.

Finally the access list is configured to prevent SNMP access for the NMS host. The example is given below.

What is SNMP?
What is SNMP?

SNMP Security Level

It defines the security algorithms to be performed on SNMP packets. They are only used in SNMPv3. There are three types of these:

noAuthNoPriv -
It uses the community string for security level authentication (no authentication, no privacy) and encryption is not used for privacy.

authNopriv - This security level (authentication, no privacy) uses HMAC and Md5 for authentication and no encryption for privacy.

authPriv - It uses Md5 or SHA with HMAC for security level (authentication, privacy) authentication and DES-56 algorithm for encryption.

Thank you so much for reading the What is SNMP? you can ask question in comments.

Also read :

What is dhcp ?


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