Licensing Requirements

Nessus is available to operate either as a subscription or managed by Nessus requires a plugin feed Activation Code to operate in subscription mode. This code identifies which version of Nessus that Tenable licensed you to install and use, and if applicable, how many IP addresses you can scan, how many remote scanners you can link to Nessus, and how many Nessus Agents you can link to Nessus Manager. Nessus Manager licenses are specific to your deployment size, especially for large deployments or deployments with multiple Nessus Manager instances. Discuss your requirements with your Tenable Customer Success Manager.

Tenable recommends that you obtain the Activation Code before starting the installation process, as it is required before you can set up Nessus.

Your activation code:

  • is a one-time code, unless your license or subscription changes, at which point Tenable will issue you a new activation code.
  • must be used with the Nessus installation within 24 hours.
  • cannot be shared between scanners.
  • is not case-sensitive.
  • is required to manage Nessus offline.

    Note: For more information about managing Nessus offline, refer to the Nessus User Guide.

You may purchase a Nessus subscription through the Tenable, Inc. online store at or via a purchase order through Authorized Nessus Partners. You will then receive an Activation Code from Tenable, Inc.. This code will be used when configuring your copy of Nessus for updates.

Note: See the Obtain an Activation Code page for instructions on how to obtain and use an Activation Code.

If you are using to manage your Nessus scanners, the Activation Code and plugin updates are managed from You must start Nessus before it communicates with, which it normally does not do without a valid Activation Code and plugins. To have Nessus ignore this requirement and start (so that it can get the information from, when you register your scanner, select Managed by SecurityCenter.