SNMP community strings for free open-source network monitoring

N10-009 By islever Editorial Last updated Nov 1, 2026

Given a scenario, use network monitoring technologies. Explain common networking ports, protocols, services, and traffic types. Explain the importance of basic network security concepts.

Short answer

A Configure SNMP with read-only community strings so a free open-source NMS can poll devices and feed a monitoring dashboard.

Question

A network administrator needs to set up a network monitoring solution. It must have the following features:
• Ability to define read-only users
• Community strings for authentication
• Availability as a free open-source software
• Ability to feed a dashboard
Which of the following should the administrator do to complete this task?

Configure SNMP. Correct Answer
Enable TACACS.
Set up LLDP.
Implement a SIEM.

Key Takeaways

The question tests whether you can map read-only community-string authentication and dashboard polling to SNMP rather than AAA, discovery, or SIEM tooling.

SNMPv1/v2c community strings provide read-only access for free open-source network monitoring tools to poll devices and populate dashboards. This N10-009 question therefore points to configuring SNMP (A).

Common mistake: A common wrong choice is a SIEM (D): SIEMs consume and correlate logs but do not use SNMP community strings and are not inherently free open-source monitoring pollers.

Expert Analysis

Match the mandatory features

The scenario lists four requirements: define read-only users, use community strings for authentication, remain free open-source, and feed a dashboard. The phrase community strings is the decisive protocol-level clue. SNMPv1 and SNMPv2c authenticate manager requests by sending a community string with each operation; a read-only community string permits polling MIB objects without allowing configuration changes. That satisfies both the read-only and community-string bullets. The dashboard requirement is met by an SNMP manager or NMS, such as Zabbix or Cacti, polling the device's OIDs and rendering returned counters. The question asks what the administrator should do, not which product to install, so configuring SNMP on the monitored devices and management station is the direct action.

Trace the data path

First, the administrator configures an SNMP agent on each monitored device and defines a read-only community string. Next, the free open-source NMS is configured with the same community string and target addresses. The NMS periodically sends SNMP GET requests; the agent checks the community string and returns only allowed MIB values. The NMS stores those values and feeds its dashboard. The permission boundary is enforced at the agent when it decides whether the supplied community permits read access. No user account database or TACACS+ authorization exchange is needed for the stated model.

Eliminate the alternatives

Option B TACACS+ is an AAA protocol for authenticating and authorizing administrative access; it does not use SNMP community strings and does not itself provide monitoring dashboards. Option C LLDP is a Layer 2 neighbor-discovery protocol; it can expose topology information but does not provide read-only users or community-string authentication. Option D SIEM can be free/open-source and can have dashboards, but it primarily ingests logs and events and does not satisfy the specific community-string requirement. A comment on this question makes exactly that link: SNMP's community strings, including public for read-only access, fit the requirements, and free open-source tools such as Zabbix or Cacti can collect metrics for dashboards. Therefore A is correct.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When a scenario lists protocol-specific authentication such as community strings, scan options for that exact mechanism before considering broad platforms. SNMPv1/v2c uses read-only and read-write community strings, while TACACS+ is AAA and LLDP is Layer 2 discovery. Treat free open-source as a hint toward an NMS like Zabbix or Cacti that polls SNMP OIDs; a SIEM may be open-source but does not answer the community-string requirement. Match each bullet to one option and eliminate any choice that misses a mandatory feature.

Frequently Asked Questions

Why does SNMP satisfy the read-only and community-string requirements?

SNMPv1/v2c agents authenticate managers with community strings, and a read-only community string lets the NMS retrieve OIDs without changing device configuration.

Can a SIEM also feed a dashboard and be open source?

Yes, some SIEMs are open source and have dashboards, but they typically collect logs and events rather than using SNMP community strings, so they miss a stated requirement.

Is LLDP a suitable monitoring solution for this scenario?

LLDP advertises neighbor and port information at Layer 2, but it does not provide read-only users, community-string authentication, or the polling data model expected by an SNMP-based dashboard.

More N10-009 FAQ →

Community Votes

100%

100% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 1 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 1

ERB14 👍 1 Answered A

SNMP (Simple Network Management Protocol): Uses community strings (e.g., standard "public" strings for read-only access) as a basic form of authentication. It is an open-standard protocol natively available across devices and free/open-source network monitoring software (like Zabbix or Cacti) to collect performance metrics and feed data into monitoring dashboards.

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