On large networks, it’s clearly not practical to manage each device manually. Administrators would have to spend large portions of their time running around the network, either physically or virtually, adjusting configurations and collecting log entries. Learn how to use the Simple Network Management Protocol to monitor and manage network devices in a centralized fashion.
- [Narrator] The Simple Network Management Protocol or SNMP, provides network administrators with a means to centrally configure and monitor network devices. On large networks it's clearly not practical to manage every network device manually. Administrators would have to spend large portions of their time running around the network, either physically or virtually, adjusting configurations and collecting log entries. This is time consuming work that is not particularly productive.
SNMP automates many of these tasks, performing the heavy lifting for administrators, who can then spend their time doing design work or higher level monitoring. Let's take a look at how SNMP works. There are three components involved in SNMP network administration. Managed devices are all of the network devices around your organization. These include routers, switches, wireless access points, firewalls and any other device that supports SNMP.
The SNMP agent is a piece of software that runs on the managed device, and allows it to communicate with the SNMP service. Most often the SNMP agent is built in to the network device's software. The network management system is the central system responsible for communicating with SNMP agents and managing the network. Under normal circumstances, the network management system reaches out to the agents on a periodic basis and requests whatever information administrators configured it to retrieve.
This might include information about network activity, device performance, or other metrics. When the network management system wants to retrieve information from a managed device it sends an SNMP command called a GetRequest, and the managed device then sends the information back in an SNMP response. The network management system can also reconfigure devices when necessary. For example, the administrator might want to push out commands to all wireless access points telling them to broadcast a new SSID.
The network management system sends these commands using an SNMP set request, telling the agent to set a configuration on the device. The agent then sends back an SNMP response, telling the network management system whether the configuration setting was successfully applied or not. Managed devices may also initiate communication with a network management system when they have unusual news to report. In this case the agent sends an SNMP trap to the network management system, which can then respond appropriately.
For example, if a network link goes down on a router, the router may send an SNMP trap to the network management system informing it of this event. The management system may then respond by sending alerts to network administrators. The current version of SNMP is version three. Administrators should be sure to use this version on all network devices because earlier versions have known vulnerabilities, including sending passwords in clear text. SNMP provides network administrators with a valuable tool to efficiently manage networks.
Learn about communication and networking best practices, including TCP/IP networking, network security devices, and secure network design and management. Instructor and cybersecurity expert Mike Chapple also includes coverage of converged protocols, network encryption, and wireless networking. You can find Mike's companion study books for this series at the Sybex test prep site and review the complete CISSP Body of Knowledge at https://www.isc2.org/cissp-domains/default.aspx.
- IP addressing
- Switches and routers
- Content distribution networks
- Designing secure networks
- Specialized networking
- Managing secure networks
- Working with virtualized networks like SDNs
- Detecting and preventing network attaches
- Transport encryption
- Wireless networking
- Host security