Hello, everyone!
Today I will show you the SNMP configuration. Before the commands, I will briefly explain this main protocol for management and monitoring.
SNMP is an abbreviation from Simple Network Management Protocol. This is a very useful protocol for manage and monitor network devices on the TCP/IP networks. SNMP belongs to the application layer.
SNMP protocol is composed of four main segments: SNMP manager, SNMP agent, MIB (Management Information Base) and managed device. These components we can see in the next figure.
Fig. 1. Components of the SNMP protocol
(https://support.huawei.com/enterprise/en/doc/EDOC1100086963)
The NMS (Network Management System) is the SNMP manager – the NMS software on the NMS server. It is the main component of this protocol. The NMS uses SNMP messages to manage and monitor network devices in the domain of work. SNMP manager sends requests to SNMP agents to query or modify parameters, and it receives SNMP traps from SNMP agents.
Every managed network device has an SNMP agent, a MIB and multiple managed objects.
The SNMP agent is a process on the network device. SNMP manager sends request messages to the SNMP agent. Then, SNMP agent has to perform an action, and return the response message to the SNMP manager. The SNMP agent reads and writes to the MIB.
The SNMP agent does not send a request message to the SNMP manager. It only sends trap messages in case a problem occurs. These are alarm messages. The SNMP agent only sends trap messages if it is configured to send.
A MIB is Management Information Base, it is located on the managed network device. This segment of the SNMP defines the attributes – name, status, data type, etc. It is used a tree structure to store data.
There are three versions of this protocol: SNMPv1, SNMPv2c, and SNMPv3. In this article, I will show commands for SNMPv2c. The main difference between these versions is in security and in the messages that are exchanged.
SNMPv1 is the first version with minimum management functions, a limited number of error codes in packets and low security. The low security is a consequence of use community names for authentication.
SNMPv2c is the next version with additional improvements over the earlier version. Authentication is the same as the SNMPv1 – community names. Because it, this version has low security. In this version, functionalities have been improved, such as: standard error codes, data types (Counter64 and Counter32) and new messages were introduced: GetBulk and Inform.
SNMPv3 is the last version of SNMP protocol, and it is recommend for use. This version uses the same messages as SNMPv2c, but SNMPv3 has very good security. It provides authentication and encryption based on the USM (User-based Security Module) and VACM (View-based Access Control Model).
Version | User verification | Encryption | Authentication |
SNMPv1 | No | No | No |
SNMPv2c | No | No | No |
SNMPv3 | Yes | Yes | Yes |
I will continue this article.
Thank you!
Reference:
Training material for HCIP Acess, V2.5
