What Is Simple Network Management Protocol (SNMP): A Complete Guide

Ever wonder how network admins keep tabs on sprawling networks? How do they spot potential bottlenecks before they cause outages?

The secret weapon is often Simple Network Management Protocol (SNMP)—a widely used protocol for managing and monitoring network devices such as routers, switches, and servers. It allows IT network administrators to track performance and gather critical data to ensure their network(s) runs smoothly.

An estimated $4.9 trillion was spent on IT hardware globally in 2023; a good chunk of which went toward network infrastructure. When you invest sizable sums in network hardware, you want to ensure your setup performs at its best.

SNMP enables efficient network administration, which contributes to effective operational performance. To help understand SNMP’s role in network management, we break down how it works as well as its benefits, versions, and challenges.

How Does Simple Network Management Protocol Work?

SNMP works using three central components:

The SNMP Manager acts as the system’s nerve center. It collects critical data from all connected network devices. Besides receiving alert messages, it also requests specific operational information. The SNMP manager is sometimes called the network management station – NMS.
An SNMP Agent is software that runs on a managed device and gathers and stores data about the device’s activities. It transmits data to the SNMP manager and responds to requests from the manager for specific information.
The Management Information Base (MIB) stores data acquired from each device and serves as a shared database for the agent and the SNMP manager.

SNMP operations

In a typical setup, the SNMP manager polls (requests information from) the SNMP agents on managed devices to collate data. The agents respond with data from their MIBs. SNMP also supports unsolicited messages—in particular, alerts—sent by the agents to the manager. These alerts are called traps.

Traps are triggered and sent to the SNMP manager when critical events occur, such as high CPU usage, failed hardware, or unusual traffic., failed hardware, or unusual traffic.

Two more standard protocols/definitions are key to understanding SNMP:

Protocol Data Units (PDUs) are SNMP messages or queries to agents for specific information. For example, asking for the current CPU usage of a router.
An Object Identifier (OID) is a unique address that identifies specific objects (e.g. metrics and statuses) within a device’s MIB.

SNMP monitoring tools

As you would imagine, SNMP generates a wealth of information in the form of traps, status reports, and other communications. To make this data available in simple formats like graphs and dashboards, SNMP monitoring tools are used.

A well-organized SNMP produces valuable insights for the IT team. Here are examples of how this visibility helps:

Network administrators can track almost any data value they specify using the protocol.
Administrators can monitor performance and manage devices across their networks, including drilling down into the stats for each device.
They are able to identify issues and troubleshoot quickly.
Traps help admin respond to potential problems in real-time, enabling swift remedial action.

It’s fair to say that without SNMP monitoring, administrators would struggle to control and monitor devices on their networks.

How do you set up SNMP on a network?

Setting up SNMP involves configuring devices, agents, and managers. It also requires defining MIBs and OIDs, as well as testing.

Here is a broad breakdown of the process:

Enable configurations on devices: SNMP is typically preconfigured on devices by the vendor. Administrators must enable the SNMP service, allowing routers, switches, etc. to store their performance stats. Configuration steps will vary depending on the vendor and model.
Configure SNMP agents: Install and run the SNMP agent software on devices to enable data collection, storage, and sharing.
Define MIBs and OIDs: Define the MIBs and OIDs for the metrics and values you want to monitor. Before configuring SNMP settings, download and import the Management Information Base database to facilitate easy analysis and interpretation.
Set up an SNMP manager: Set up SNMP management software to implement your central management station.
Test: Test the configuration with SNMP queries and traps. The goal of this basic test is to ensure the device is accessible, correctly configured, and has a sound connection.

What Network Devices Does SNMP Monitor?

This network management system can manage numerous devices. Here are typical examples:

Servers (database, mail, web, application, file servers)
Routers that connect different networks and direct data between them (e.g. connecting a LAN to the internet)
Switches that connect and direct data to local area network devices.
Workstations, including computers
Printers and copiers
Security firewalls
CCTV cameras and temperature/humidity sensors
Uninterruptible Power Supply (UPS) devices
Load balancers, which regulate incoming traffic across servers to prevent overloads.

What Issues Does SNMP Detect?

By closely monitoring SNMP devices, administrators can detect network issues such as:

Device failures: SNMP detects when devices like routers and switches go offline or malfunction.
Server overload: The system red flags a server that might be about to crash.
High CPU utilization: It can monitor and raise an alert about high CPU usage.
Configuration changes: The protocol can help detect unauthorized or unexpected configuration changes on network devices.
Interface errors: It can detect errors on network interfaces such as CRCs (data packets corrupted during transmission) and if a network interface becomes unavailable.
Bandwidth usage: SNMP monitors bandwidth utilization and can alert administrators if usage is straining the limit.
Network latency: Network monitoring tools alongside SNMP measure latency (how long it takes for data to travel from the source to the destination across a network) and identify performance bottlenecks.
Temperature and environmental conditions: Monitoring temperature and other environmental conditions within the network helps prevent overheating and potential equipment malfunctions.

What Are The Benefits Of SNMP?

Simple Network Management Protocol delivers several important benefits, including:

Centralized management: The network management system enables administrators to manage multiple SNMP entities from a central location.
Proactive issue detection: Alerts and traps allow administrators to address minor issues proactively before they become major problems.
Real-time monitoring: It provides real-time data on the status and health of network components and devices.
Troubleshooting: SNMP helps in identifying and resolving network issues swiftly.
Remote configuration: It supports remote configuration and troubleshooting of devices and issues.
Scalability: SNMP can be used to manage large and complex networks efficiently.

Overall, it plays a vital role in helping administrators keep managed devices up and running and the network performing as it should.

What Are The SNMP Protocol Versions?

There are three SNMP versions:

SNMPv1: This is the original version of the protocol (Protocol reference: RFC 1157, defined by the Internet Architecture Board). It’s relatively simple to set up but inadequate and not as secure for many modern business networks. It uses plain-text community strings, which are like passwords, to enable access to data. This form of authentication is notoriously weak.
SNMPv2: The second version of the network management tool (Protocol reference: RFC 1441–RFC 1452) represents a step forward in performance and flexibility. However, it retains the use of community strings, rendering security sub-optimal.
SNMPv3: Version 3 is the latest protocol (Protocol reference: RFC 3410–RFC 3418). It incorporates enhanced performance and security features. In-built authentication measures and encryption guard against unauthorized access attempts by hackers.

SNMPv3 is currently the most secure and widely recommended version for network monitoring. With technology and connectivity advancing relentlessly, the older versions have fallen behind the curve.

Best practice recommends deploying Version 3 and disabling SNMPv1 and v2 where possible.

What Are The Challenges Of SNMP?

The main challenges SNMP presents are:

Security vulnerabilities

Earlier SNMP versions (SNMPv1 and SNMPv2) have weak security because they transmit data in plain text (without encryption).

While SNMPv3 offers better security, it must be properly configured to protect against interception effectively. Even then, it is not immune from breaches and attacks.

Complexity

Setting up and managing SNMP agents, managers, and MIBs can be complex. This is especially true of larger sophisticated networks where getting the best information at the right time may be a challenge.

Configuration errors

Misconfigurations in SNMP, such as errors in community strings, Access Control Lists (ACLs), and trap destinations, can compromise monitoring and the network overall.

Resource consumption

Regular polls (information requests) and ongoing data collection consume network bandwidth and device resources. This can drag down network performance.

Lack of standardization

The lack of standardization in manufacturers’ extensions to the basic SNMP MIB is a recognized problem.

Additional tools

SNMP might not provide all the insights you need to manage your setup optimally. You may need to use additional tools in conjunction with SNMP to get the network visibility you want.

How Can Homefield IT Help You With SNMP And Network Management?

As a long-established provider of complete managed IT solutions to small businesses and larger enterprises across the United States, Homefield IT helps hundreds of clients keep their networks in tip-top health.

Our comprehensive network management services include:

Design and Implementation
Network performance optimization
Maintenance and troubleshooting
Network security services
Simple Network Management Protocol (SNMP)

Regarding SNMP, we can help you with all aspects of the protocol. We cut through the complexity and assist with expert SNMP setup and configuration. Furthermore, we help you optimize your network and offer premium 24/7 support, monitoring, and maintenance of this vital infrastructure.

With the average cost of data breaches at $4.88 million in 2024, security must be front of mind for all organizations. We know that earlier SNMP versions are vulnerable to eavesdropping, message tampering, and unauthorized access. Additionally, SNMPv3 is susceptible to threats like Denial-of-Service (DoS) and spoofing attacks.

That’s why we assess your network vulnerabilities and introduce advanced measures to bolster your cyber defenses.

We also leverage the latest SNMP monitoring tools to ensure you get the best data from managed devices, presented in easily digestible and actionable formats to facilitate super-responsive and effective network administration.

Contact Homefield IT today to discuss peak network performance.

FAQ’s

Is SNMP still a relevant network management system today?

Some IT professionals consider SNMP outdated, but it remains relevant and widely used in network management today. Its simple setup and administration make it suitable for networks that do not require in-depth, sophisticated monitoring. It offers a dependable, well-understood standard; completely replacing SNMP would require replacing many network devices.

That being said, some modern alternatives like streaming telemetry and cloud-based monitoring are gaining popularity for real-time data collection and process automation.

What is the difference between SNMP and SMTP?

Simple Mail Transfer Protocol (SMTP) is a standard, specifically relating to the sending and receiving of email messages. It is used to monitor the health of devices in your email network and transfer emails between servers.
Simple Network Management Protocol (SNMP) is an industry-standard protocol for monitoring devices and improving performance on networks.

What are common SNMP commands?

Some of the most common SNMP commands are:

GET = retrieve information from a device
START = initiates an SNMP session
GETNEXT = fetch the next value in the MIB
GETBULK = retrieve large data sets
WALK = retrieves a tree of information
TRAP = enables notifications for critical events

Can SNMP be used for network security?

SNMP alone is not a reliable security monitoring tool. It is designed to monitor network performance and manage devices. However, it can assist in detecting potential security issues like unusual traffic patterns and configuration changes.

For comprehensive security monitoring, SNMP is often used in conjunction with other security systems such as Intrusion Detection Systems (IDS) and Security Information and Event Management (SIEM) systems. These security-focused tools incorporate more robust and comprehensive protection against cyber threats.

What is a user datagram protocol in SNMP?

In SNMP, the User Datagram Protocol (UDP) is the primary transport protocol for communication between SNMP managers and agents. UDP is a lightweight protocol that enables fast, efficient data transmission. However, UDP does not provide error correction or retransmission, so SNMP relies on its own processes for handling lost or missing data.

Find out how Homefield IT can turbocharge your technology.