A VPN is the best choice because it is designed to provide secure remote access to an internal network over the Internet by creating an encrypted tunnel. Once the VPN is established, the remote user’s device effectively becomes part of the corporate network and can use the appropriate tools for each server type (for example, SSH to Linux and RDP to Windows) without exposing those management services directly to the public Internet. Quentin Docter explains that a VPN “extends your company’s internal network across the Internet,” creating a private connection through “encryption and encapsulation,” and that the host becomes part of the internal network (often receiving an internal IP). The All-in-One guide reinforces this by describing VPNs as an encrypted tunnel over the open Internet.

By comparison, RDP is “used exclusively with Microsoft operating systems,” so it doesn’t meet the Linux requirement. FTP is for file transfers, not full secure remote access, and RMM is primarily for centralized IT monitoring/management rather than a general user remote-access method.