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N2OS Software Development Kit
The N2OS Software Development Kit (SDK).
Scriptable variables
The scriptable variables correlation feature allows users to implement custom checks on the way variable values change over time. This section covers how such scripts can be implemented and used.
Setup
Do this procedure to add a script for custom variables correlation.

Resources
- Release Notes
  Access the release notes for release-based products.
- N2OS Configuration
  The N2OS Configuration - Reference Guide.
- N2OS Software Development Kit
  The N2OS Software Development Kit (SDK).
  - Scriptable protocols
    The Lua scripting API for building a custom protocol decoder.
  - Scriptable variables
    The scriptable variables correlation feature allows users to implement custom checks on the way variable values change over time. This section covers how such scripts can be implemented and used.
    - Setup
      Do this procedure to add a script for custom variables correlation.
    - Writing a variables correlation script
    - API reference
  - OpenAPI
    The scriptable variables correlation feature allows users to implement custom checks on the way variable values change over time. This section covers how such scripts can be implemented and used.
  - Data model reference
    The data model reference for query entities.
  - Data integration best practices
    A description of best practices when using Nozomi Networks data integration with Syslog integration or OpenAPI calls.
- Integration Guides
  Integration guides to help you use applications that integrate with Nozomi Networks products.
- Reference Guides
  Additional reference guides with information on items such as Alerts and Incidents and Federal Information Processing Standards (FIPS).
- Quick Start Guides
  Hardware Quick Start Guides.
- Security
  Stay up-to-date with the most recent information and solutions for all vulnerabilities that affect Nozomi Networks products.
- Print format documentation
  A list of all the technical documentation that is available in print format.
- Documentation archive
  Access previous versions of the technical documentation.

Setup

Do this procedure to add a script for custom variables correlation.

Copy the Lua script in /data/scriptable_variables
Configure Guardian with this rule conf.user configure vi scriptable-variable script <script_name> in command-line interface (CLI) (<script_name> is the name of the file including the extension)
Execute service n2osids stop, the intrusion detection system (IDS) process will be restarted automatically.

It is advised that after the IDS process gets restarted, the corresponding log file (n2os_ids.log) is checked:

If the script was loaded successfully, an INFO log line like the example below will have been output:
```
INFO: ScriptableVariablesScript: Successfully loaded script (script.lua)
        
```
If the script loading has failed, one or more ERROR log lines should be present in the log file, providing details on what the problem was.

After the above steps, the new scriptable variables correlation script will be loaded in Guardian and will be offered all variable updates.