Port 12489NSClient Monitoring Agent
NSClient++ (also known as NSClient or NC_Net Client) is a monitoring agent designed primarily to extend the functionality of popular network monitoring solutions such as Nagios, OP5, and Opsview. It enables the collection, aggregation, and distribution of performance metrics, health status information, and service checks from Windows-based systems, facilitating comprehensive infrastructure monitoring..
- transport
- tcp
- in transit
- cleartext
- assignment
- unofficial
- risk
- 4/10
- lookups
- 29,961
single transport
payload readable on path
used by convention
caution
rank 38 of 993 · top 4%
Technical Details
what runs on :12489NSClient++ operates as a lightweight daemon running on Windows systems, primarily designed to communicate seamlessly with Nagios and related network monitoring suites. It allows central monitoring servers to remotely execute checks, gather system metrics, and retrieve service statuses, making it simpler to track the health of Windows environments in a heterogeneous network.
Technically, NSClient++ supports multiple communication protocols, including NRPE, NSClient, NRDP, and HTTP API. This flexible support enables various methods for issuing queries and retrieving data, such as command checks, performance counters, log parsing, and external script execution, including Python, Lua, and .NET scripts. Such extensibility allows tailored monitoring solutions that can adapt to unique operational requirements.
The agent bridges the monitoring servers with Windows internals, enabling the collection of CPU, disk, memory, service status, event logs, and application-specific information. It simplifies complex scripting by wrapping native system commands or external scripts, standardizing the output for compatibility with monitoring dashboards.
Security Information
exposure of :12489risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
network services averages 3.9 across 604 ports — this one sits 0.1 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
unofficial
used by convention, not registered — what answers here varies by deployment
reachable over
tcp
every listening transport is another surface to filter at the edge
security overview
Common vulnerabilities in NSClient++ involve:
- Exposure of control and data channels if encryption and authentication are not enabled.
- Default configurations leaving management interfaces open to unauthorized access.
- Remote code execution opportunities via poorly controlled external script execution.
- Weaknesses in protocol implementations, especially if legacy or insecure configurations are used.
Mitigations include:
- Enabling SSL/TLS encryption and certificate-based authentication where possible.
- Restricting network access to trusted sources with firewalls and ACLs.
- Disabling or securing management commands that allow remote configuration or execution of arbitrary scripts.
- Keeping NSClient++ and associated libraries up to date.
- Implementing strong authentication mechanisms and monitoring access logs for suspicious activities.
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risk mix of the 8 listed
- caution100%
0 of 8 encrypted