SNMP Introduction

SNMP or Simple Network Management Protocol is a standard way of transferring information of network devices like servers, computers, routers, printers, hubs etc. Today it has become very popular and most of the hardware vendors support this protocol. SNMPv3 is the latest version of SNMP protocol.

How SNMP Works

Below are the main components of SNMP management system
1. SNMP Manager
This is the software which collects information from dofferent components in the network. Usually this is installed on a computer where network administrators have easy access. SNMP Manager polls each devices in the network regularly for information. According to your interest you can purchase or use a free SNMP Manager.

Some of the things that SNMP Manager does are

• Collects information on bandwidth usage.
• Alerts on low disk space
• Monitors disk space usage of servers
• Monitors CPU usage of servers
• Monitors Memory usage of servers
• Alerts on thresholds of disk space, memory usage and CPU usage
• Sets parameters in agents such as passwords and configurations.

2. SNMP Agent
This is a piece of software which is installed in network devices by the hardware manufacturer. If monitoring of the device is required you need to enable and configure the agent. SNMP Agents run on the devices on the network separately and responsible for collecting information and deliver to the SNMP Manager when polled. In some special situations such as in an error, the agent can initiate and send messages to the SNMP Manager even when it is not polled.

3. MIB(Management Information Base)
This is a database which is used by the manager and agents to exchange information.


SNMP uses UDP(User Datagram Protocol - used to send short messages between a client and a server) as the transport protocol.

Below are the default ports used.
UDP 161 - Manager does polling of agents via this port.
UDP 162 - Messages initiated by agents are sent to the manager via this port.