Offline Mode

You can set new or existing Tenable Nessus scanners to offline mode. Offline mode automatically disables any features that require a connection to the Tenable Nessus feed. For this reason, Tenable recommends using offline mode for any scanner that is offline or air-gapped.

Activate or Deactivate Offline Mode

  • To register Tenable Nessus in offline mode during installation, select the Register Offline option in the installation user interface.

  • To activate offline mode on an existing Tenable Nessus scanner, run nessuscli fetch --register-offline nessus.license from the command line.

  • To deactivate offline mode on an existing Tenable Nessus scanner, run nessuscli fetch --register <activation-code> from the command line.

For more information about nessuscli fetch commands, see Fetch Commands.

Offline Mode Functionality

The following features and elements are disabled in offline mode:

  • All functionality that requires connection to the Tenable Nessus feed and:

    • Core and plugin updates

    • nessuscli commands that require connection to the Tenable Nessus feed (for example, nessuscli update)

    • Feed status updates in the Events tab

    • License registration checks

  • Terrascan

  • Upgrade Assistant

  • The ability to update the plugin detail locale

  • The ability to link Tenable Nessus to Tenable Vulnerability Management

  • In-application product updates

  • Context-sensitive help documentation icons

Note: In Tenable Nessus versions 10.9.0 and later, web application scanning and declaring agent versions via agent profiles are both supported in offline mode. However, you need to run the following commands while online before going into offline mode for the features to work properly:

  • Web application scanning — nessuscli --upload-was <image-tarball path>

    Running this command uploads a local web application scanning image tarball file to Tenable Nessus. For more information, see Web application scanning in offline mode.

  • Agent versioning via agent profiles — nessuscli update <tar.gz filename> --agent-version

    Running this command adds the agent version of the tar.gz file to the Agent Profiles menu to be selectable while creating or updating agent profiles. For more information, see Manage agent profiles in offline mode.