Virtual Private Networks
VPNs are a technology that allows for the extension of a private or local network to host that might not work on that same local network.
It's a tunneling protocol.
By sending data out of this, the computer could access internal resources just like if it was physically connected to the private network.
Most VPNs work by using the payload section of the transport layer to carry an encreypted paload that actually contains an entire second set of packets.
-
This payload is carried to the VPNs endpoint where all the other layers are striped away and discarded.
-
Then the payload is unencrypted, leaving the VPN server with the top three layers of a new packet.
-
This gets encapsulated with the proper data link layer information and sent out across the network.
-
This process is completed in the inverse, in the opposite direction.
Two-factor authentication
A technique where more than just a username and password are required to authenticate.
Proxy Service
A server that acts on behalf of a client in order to access another service.
Proxies exist in almost every layer.
Common use of a web proxy today might be prevent someone from accessing sites.
Reverse Proxy
A service that might appear to be a single server to external clients, but actually represents many servers living behind it.
Reverse procies are now implemented in order to use hardware built specifically for cryptography, to perform the encryption and decryption work.
