Running Nessus Pro offline doesn't mean you should ignore security. In fact, air-gapped environments are often high-value targets.
| Step | Action | |------|--------| | 1 | Install Nessus Pro on offline machine (using downloaded .deb / .rpm / .msi ). | | 2 | Run nessuscli fetch --challenge → produces a . | | 3 | On an internet-connected machine , go to Tenable’s offline activation portal. | | 4 | Enter challenge code + serial number → generates a license file ( .lic ). | | 5 | Transfer license file to offline machine (USB, etc.). | | 6 | Import with nessuscli fetch --register-offline license.lic . | | 7 | Restart Nessus service. | nessus pro offline activation