remote access

A remote access service (RAS) is any combination of hardware and software to enable the remote access tools or information that typically reside on a network of IT devices.
A remote access service connects a client to a host computer, known as a remote access server. The most common approach to this service is remote control of a computer by using another device which needs internet or any other network connection.
Here are the connection steps:

User dials into a PC at the office.
Then the office PC logs into a file server where the needed information is stored.
The remote PC takes control of the office PC's monitor and keyboard, allowing the remote user to view and manipulate information, execute commands, and exchange files.
Many computer manufacturers and large businesses' help desks use this service widely for technical troubleshooting of their customers' problems. Therefore you can find various professional first-party, third-party, open source, and freeware remote desktop applications. Which some of those are cross-platform across various versions of Windows, macOS, UNIX, and Linux. Remote desktop programs may include LogMeIn or TeamViewer.
To use RAS from a remote node, a RAS client program is needed, or any PPP client software. Most remote control programs work with RAS. PPP is a set of industry standard framing and authentication protocols that enable remote access.
Microsoft Remote Access Server (RAS) is the predecessor to Microsoft Routing and Remote Access Server (RRAS). RRAS is a Microsoft Windows Server feature that allows Microsoft Windows clients to remotely access a Microsoft Windows network.

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