SNMP (Simple Network Management Protocol) is a network device management protocol running on the application layer of the OSI model.
What is SNMP?
The SNMP enables the management and monitoring of network devices. With this protocol, the management of the network devices such as Router, Switch, Hub, Bridge, Server, Printer, Modem can be controlled easily. And even a UPS with a network card can be managed and monitored.
SNMP is officially described in the IETF. Managing all network devices in a large network is not an easy task. With SNMP, you can easily manage devices by remotely accessing devices. For example, a monitoring method related to CPU usage of Router A can be created.
It also uses the UDP 161 port for public messages and the UDP 162 port for Trap messages.
What Does It Do?
The entire network can be easily monitored and controlled via SNMP. With the SNMP, the bandwidth utilization of the Internet connection, the CPU temperature of the computer, and the heavy traffic in the network can be monitored.
Therefore, the performance of a network that can be monitored and managed can be improved. Bandwidth can be tested by monitoring a Web Server on the network and abnormal traffic can also be monitored during attacks on your Web Server.
Any network device with a network card and an IP address can be managed and monitored with this protocol. There are components that SNMP uses to accomplish so many tasks.
1. Management Station
The computer that the manager uses to monitor and manage the network and that has SNMP software installed.
2. Management Agent
SNMP agent software integrated into the managed device.
3. Management Information Base (MIB)
All information collected by the management agent is stored in the MIB database. The Management Station obtains the necessary information using the MIB database. In addition, the information in the Databases can be checked by changing.
4. Network Management Protocol
The network management protocol is used to establish communication between the management station and the management agent.
SNMP versions are explained in 3 groups. Let’s look at the SNMP versions.
SNMPv1: It is the first version of the SNMP protocol and is defined in RFC 1157.
SNMPv2: In SNMP version 2, error handling and efficiency improvements have developed. It is described in detail in RFC 1901.
SNMPv3: This version has improved security and privacy. SNMPv3 version is defined in RFC 3410.
How It Works?
The network management system is based on two main elements; a supervisor and intermediaries. The supervisor is the terminal that allows the network administrator to make management requests.
Agents are entities at each interface level. It connects managed devices to the network and allows information to be collected about different objects.
Switches, Hubs Hubs, Routers, and Servers are examples of hardware that includes managed objects. These managed objects can be hardware information, configuration parameters, performance statistics, and other items directly related to the hardware’s behavior being executed.
These items are classified into something similar to the database called MIB (“Management Information Database”). SNMP allows dialogue between the auditor and the representatives to collect the necessary objects in the MIB.
Now let’s answer how SNMP works. The SNMP management station sends a request to gather information from the network devices in the network. The information to be collected is collected and evaluated by the request management representative. As a result, information collection is completed by submitting requests to the request management station.
In the SNMP information collection phase, a method called Trap is available. What is Trap?: The trap is used to generate an alarm. This alarm occurs when a certain condition is met.
Management agents can be made more efficient by configuring with Trap. For example; If it is desired to check traffic conditions that can be accessed by a specific interface of a network device, a trap is generated for it and configured with trap rules. The controlled interface sends a report to the management station at a specified rule.
By creating Traps with SNMP 3rd party software, we can reduce the request for management station information collection. As a result, we reduce network usage to a minimum.
We have mentioned above how SNMP works at the application layer. You can easily find SNMP software on the Internet. To give an example of SNMP software;