Definitions for "Tunnel Mode"
Keywords:  ipsec, vpn, payload, header, esp
An IPsec (ESP or AH) mode that is applied to an IP tunnel, where an outer IP packet header (of an intermediate destination) is added on top of the original, inner IP header. In this case, the ESP or AH transform treats the inner IP header as if it were part of the packet payload. When the packet reaches the intermediate destination, the tunnel terminates and both the outer IP packet header and the IPsec ESP or AH transform are taken out.
The process of tunneling, as opposed to "transport mode."
ESP mode that encrypts an entire IP packet including the IP header.