A VPN (Virtual Private Network) is a dedicated connection to a LAN (Local Area Network) via the internet. When connected via a VPN connection, a Local Area Network is not restricted by the limitations regarding physical cables, and the local network can therefore connect to the internet through a VPN client.
VPNs can be typically characterized as host-to-network or remote access by connecting a single computer to a network or as site-to-site for connecting two networks.
Common tunneling protocols
- IP in IP (Protocol 4): IP in IPv4/IPv6
- SIT/IPv6 (Protocol 41): IPv6 in IPv4/IPv6
- GRE (Protocol 47): Generic Routing Encapsulation
- OpenVPN (UDP port 1194): Openvpn
- SSTP (TCP port 443): Secure Socket Tunneling Protocol
- IPSec (Protocol 50 and 51): Internet Protocol Security, IKEv1 and IKEv2 modes). Tunnel and transport modes.
- L2TP (Protocol 115): Layer 2 Tunneling Protocol
- VXLAN (UDP port 4789): Virtual Extensible Local Area Network.