ELI5: What is a VPN? Why is it important to have on on a mobile device?
A VPN is a “virtual private network”.
Logically, it is a “tunnel” which shields your internet traffic from being directly viewed. This is done by using software to establish a virtual interface, or endpoint, on your system. This allows your computer to remotely participate in a protected network remotely.
Your computer or device will talk to a server or routing device on a remote network and negotiate a session. When the session has been established, all private network packets will be encrypted, wrapped up in a regular packet (encapsulated) and sent across the internet to the server or routing device.
The server or router also has a virtual (software, not physical) interface (port) which is used for maintaining the session and sending VPN data, encrypting/decrypting data and directing VPN traffic to other participants in the virtual private network. When the device or server gets the packet, it knows how to decrypt and unpack the regular packet and read the data you wrapped up in it. Once it has unpacked the packet, it will send the unpacked packet to the intended destination, or to a device that knows how to get it to the intended destination.
VPNs are used to protect information or activities from people who might intercept your data on the way to a remote server or system. By using a VPN, you can safely access systems inside a remote network from far away without worrying about intercepted data being read and used. You don’t need a VPN to safely use the internet, but if you work remotely from your device or want to mask what you’re doing from outsiders, you can use a VPN.
VPN = Virtual Private Network
This is a secure network connection that is designed to be a direct access tunnel between two networks.
It’s only important on a mobile device if there is secure information that is being accessed via that mobile device. Since most mobile devices do not adequately have security protocols in place to be compliant with that network, a VPN is used to connect.
Popular home use of VPNs is to hide shit like torrents and whatnot.
Businesses, OTOH, want to tightly restrict access to their internal systems. For a business user, you might be required to have the VPN to even read your mail or access some shared folders.
Or, for a lot of IT workers, access to the work networks also require VPN to do the work securely. It’s also a way to bridge two or more remote networks for common use.
In layman’s terms, that means that it can look to outside computers like you’re actually on the network you’re VPNed into.
In my case, I can VPN into my University’s network, and scholarly journal sites see my traffic coming from the university’s network. They will let me download scholarly articles because my university has a subscription.