Changes

[[File:Configuration examples ipsec scheme 2.png]]

[[File:Configuration examples ipsec scheme 2.png]]

As mentioned earlier, ''configuration scheme 2'' (figure above) is an extension of ''configuration scheme 1''. While ''configuration scheme 1'' only depicts a connection between two IPsec instances, you can see that in ''configuration scheme 2'' additionally contains two end devices ('''END1''' and '''END2'''), each connected to a separate router's LAN. When this scheme is realized, not only will the two routers be able to communicate with each other, the end devices will also be reachable to one another and from each router.

As mentioned earlier, ''configuration scheme 2'' (figure above) is an extension of ''configuration scheme 1''. While ''configuration scheme 1'' only depicts a connection between two IPsec instances, you can see that ''configuration scheme 2'' additionally contains two end devices ('''END1''' and '''END2'''), each connected to a separate router's LAN. When this scheme is realized, not only will the two routers be able to communicate with each other, but the end devices will also be reachable to one another and from each router.

It should also be noted the connection type used is '''Tunnel''' and not '''Transport'''. Tunnel protects the internal routing information by encrypting the IP header of the original packet. The original packet is encapsulated by a another set of IP headers. Transport encrypts only the payload and Encapsulating Security Payload (ESP) trailer; so the IP header of the original packet is not encrypted. Transport mode is usually used when another tunneling protocol (such as [[VPN#GRE_Tunnel|GRE]], [[VPN#L2TP|L2TP]]) is used to first encapsulate the IP data packet, then IPsec is used to protect the GRE/L2TP tunnel packets.

It should also be noted the connection type used is '''Tunnel''' and not '''Transport'''. Tunnel protects the internal routing information by encrypting the IP header of the original packet. The original packet is encapsulated by a another set of IP headers. Transport encrypts only the payload and Encapsulating Security Payload (ESP) trailer; so the IP header of the original packet is not encrypted. Transport mode is usually used when another tunneling protocol (such as [[VPN#GRE_Tunnel|GRE]], [[VPN#L2TP|L2TP]]) is used to first encapsulate the IP data packet, then IPsec is used to protect the GRE/L2TP tunnel packets.

Tunnel is more is more widely implemented in site-to-site VPN scenarios and supports NAT traversal, that's why we chose it for the example.

Tunnel is more widely implemented in site-to-site VPN scenarios and supports NAT traversal, that's why we chose it for the example.

==Router configuration==

==Router configuration==