What are the 5 basic commands of SNMP?

The five basic commands of SNMP (Simple Network Management Protocol) are used for managing and monitoring network devices and systems. These commands include:

1. GET: Retrieves the value of a specified object or variable from an SNMP agent running on a network device. It is used to query the current status or configuration of a device.
2. GETNEXT: Retrieves the value of the next object or variable in the MIB (Management Information Base) hierarchy. It is used for sequential retrieval of MIB objects.
3. SET: Modifies the value of a specified object or variable in the SNMP agent’s MIB. It allows administrators to configure and control network devices remotely.
4. GETBULK: Retrieves large amounts of data from an SNMP agent in a single request. It is more efficient than multiple GETNEXT requests for retrieving large datasets.
5. TRAP: Asynchronous notification sent by an SNMP agent to an SNMP manager to indicate events or conditions, such as device restarts, link status changes, or system errors.

SNMP command refers to any of the above commands used in the SNMP protocol to manage and monitor network devices. These commands are exchanged between SNMP managers (network management systems) and SNMP agents (network devices) to retrieve status information, configure settings, and receive notifications about network events.

There are primarily three versions of SNMP used in network management:

1. SNMPv1: The first version of SNMP, which provides basic management capabilities such as GET, GETNEXT, and SET commands. It uses community strings for authentication and operates over UDP.
2. SNMPv2: Introduced improvements over SNMPv1, including additional protocol operations like GETBULK for efficient data retrieval. SNMPv2c (Community-Based SNMPv2) is a widely used variant.
3. SNMPv3: The most secure version of SNMP, providing authentication, encryption, and access control mechanisms. SNMPv3 addresses the security weaknesses of earlier versions by implementing user-based security model (USM) and encryption for secure communication.

The basic command for snmpwalk is used to retrieve a subtree of management values using SNMP GETNEXT requests. It allows administrators to recursively query SNMP agents for all MIB variables under a specified OID (Object Identifier). The command syntax typically includes specifying the SNMP version, community string, target device IP address, and OID subtree to walk.

The function of SNMP is to facilitate the monitoring and management of network devices and systems. It allows network administrators to remotely monitor device performance, detect faults or errors, configure device settings, and receive notifications about critical events. SNMP achieves this by using a standardized protocol for exchanging management information between SNMP managers (management stations) and SNMP agents (managed devices), enabling centralized network management and troubleshooting capabilities across diverse network environments.