Mirroring External Resources
If an organization blocks the servers performing dependency-check scans from downloading content on the internet they will need to mirror two data sources: The NVD API and the Retire JS repository.
Creating an offline cache for the NVD API
The Open Vulnerability Project's vuln CLI can be used to create an offline copy of the data obtained from the NVD API. Then configure dependency-check to use the NVD Datafeed URL.