Airgapped Networks

Security Onion is commited to allowing users to run a full install on networks that do not have Internet access. Starting in 2.x RC3, users will see an option to specify that the install is airgapped. The installer will then make the appropriate modifications to make this work properly.

Key Differences

By selecting Airgap as an install option, a couple of things happen that are different than a normal install with Internet access. First, all CentOS repos are removed and replaced with a new repo that runs on the manager. During the install, all of the necessary RPMs are copied from the ISO to a new repo located in /nsm/repo/. All devices in the grid will now use this repo for updates to packages. Another difference is the latest ET Open rules from Emerging Threats are copied to /nsm/repo/rules/ so that the manager can access them. This allows users to use the standard SO process for managing SIDS etc. Finally, yara rules for Strelka are copied to /nsm/repo/rules/strelka/ so that Strelka has the latest and greatest rules for static file analysis.

Updating

Starting with GA, airgap installs will use soup to update the environment. soup will be able to automatically detect that it is an airgap install. It will require the user to mount the newest install ISO on the Manager so that soup has access to the files located there. It will copy over all of the latest docker images, OS RPMs, and Security Onion code, and then perform the upgrade. This will reduce the complexity from previous versions and help promote frequent updates for airgap installs.