Hi
When IPSec tunnel mode is used, IPSec encrypts the IP header and the payload, whereas transport mode only encrypts the IP payload. Tunnel mode provides the protection of an entire IP packet by treating it as an AH or ESP payload. With tunnel mode, an entire IP packet is encapsulated with an AH or ESP header and an additional IP header. The IP addresses of the outer IP header are the tunnel endpoints, and the IP addresses of the encapsulated IP header are the ultimate source and destination addresses.
IPSec tunnel mode is useful for protecting traffic between different networks, when traffic must pass through an intermediate, untrusted network. Tunnel mode is primarily used for interoperability with gateways, or end-systems that do not support L2TP/IPSec or PPTP connections. You can use tunnel mode in the following configurations:
⢠Gateway-to-gateway
⢠Server-to-gateway
⢠Server-to-server
Regards
Senthil Kumar P V